 # discrete vs continuous variable

0. Edit . Spell. Mathematics. continuous. The weight of the person is actually 152.232211223342211223332112244778899399947777889999888888377747666678788992336677… Learn. Give it a try and see how good you understand it! the class containing the median. The difference between discrete and continuous variables in statistics. 148 times. → This data can be used to create many different charts for process capability study analysis. Edit. continuous. The second chart calculates the sum of profit for each month in each year for a continuous dimension. The idea behind this post is to understand two types of random variables: Discrete Random Variables and Continuous Random Variables. Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. A dog's weight is measured every week. Continuous Random Variable DRAFT. So height is a continuous random variable. Discrete variable assumes independent values whereas continuous variable assumes any value in a given range or continuum. Match the derivative rule with. Income of any household is something researchers are always very interested in. A discrete variable is always numeric. Discrete vs. Continuous vs Discrete Variables in the context of Machine Learning. Discrete Data can only take certain values. It will look like a normal distribution, except for one key distinction—normal variables are truly continuous, not discrete. Suppose listing all possible values between 0 and 1 is not possible, because there are infinite number of values between 0 and 1. While continuous-- and I guess just another definition … While continuous-- and I guess just another definition … Discrete and Continuous Random Variables: A variable is a quantity whose value changes.. A discrete variable is a variable whose value is obtained by counting.. For example, the number of customer complaints or the number of flaws or defects. Beispiele: Die Anzahl von Kundenbeschwerden oder die Anzahl von Mängeln oder Defekten. For example: Your weight. P(5) = 0 because as per our definition the random variable X can only take values, 1, 2, 3 and 4. Edit . Your weight can be any weight within the range of human weights. More data points (a larger sample) needed to make an equivalent inference. Because it would literally take forever. In fact, you would get to “forever” and never finish counting them. Transformation of A Continuous Variable into Discrete. A race can be timed to a millisecond. Learn. Discrete data is counted, Continuous data is measured . Continuous variables. Income of any household is something researchers are always very interested in. Instead it is defined over an interval of values and is represented by the area under a curve (i.e., integration). Ex: Weight of a person: 152.232 Kg, you’re probably thinking, “where am I counting?”. It can take any value in a range (or interval). Continuous data is considered as the opposite of discrete data. Because quantitative variables strive to measure quantities, they are generally divided into discrete and continuous variables. The quiz below is designed to Assesses and reinforces the student's understanding of the nature and differences of discrete and continuous data. Discrete data contains distinct or separate values. In discrete variable, the range of specified number is complete, which is not in the case of a continuous variable. The weight of a bag of apples at the grocery store. Inferences can be made with few data points—valid analysis can be performed with small samples. Write. • In discrete distributions, the variable associated with it is discrete, whereas in continuous distributions, the variable is continuous. You have discrete random variables, and you have continuous random variables. Edit. It can be measured on a scale or continuum and can have almost any numeric value. A variable is a quantity whose value changes. We cannot list or count all possible values of continuous RV. Created by. A person’s age in years. A probability distribution may be either discrete or continuous. Stetige Variablen können aus numerischen oder Datums-/Uhrzeitwerten bestehen. If we use discrete data, we only know whether someone … Meaning, it is a number with an identified minimum and maximum. I know, you don’t have time. the class containing the median. Time in a race. If a variable can take on two or more distinct real values so that it can also take all real values between them (even values that are randomly close together). Created by. So height is a continuous random variable. Continuous is opposite to discrete. For example, take age. I’m Gopal Krishna. For non-overlapping or otherwise known as mutually inclusive classification, wherein the both the class limit are included, is applicable for the discrete variable. Test. Measures can actually be used as discrete fields or continuous fields, and the same is true for some dimensions, such as dates. Match. Suppose P(X=0.234) = probability of RV X is equal to 0.234. The decision about which statistical test is appropriate under a specific set of circumstances very often depends on whether the underlying data is discrete or continuous. Terms in this set (8) The number of telephone calls received at an office for a 24 hour period. What is the difference between discrete variable and continuous variable? Solved assignment problems in communicaion |online Request, Permutations and Combinations | Probability Theory, Examples of Algorithms and Flow charts – with Java programs, What is Operating System? 41 times. And discrete random variables, these are essentially random variables that can take on distinct or separate values. So,  X is a discrete random variable. A function can be defined from the set of possible outcomes to the set of real numbers in such a way that ƒ(x) = P(X = x) (the probability of X being equal to x) for each possible outcome x. Your email address will not be published. A probability distribution is a formula or a table used to assign probabilities to each possible value of a random variable X. Learn. 73% average accuracy. The downside of discrete data is the loss of precision in measurement and the need for a larger amount of data to uncover patterns. 12th grade. Ask Question Asked 2 years, 7 months ago. Stetige Variable Stetige Daten sind numerische Variablen, die zwischen zwei beliebigen Werten eine unendliche Anzahl von Werten aufweisen. We assure you that the color-coding identifies discrete vs. continuous fields and not dimensions vs. measures. A continuous random variable takes on all possible values within an interval on the real number line (such as all real numbers between –2 and 2, written as [–2, 2]). Continuous & Aggregated vs. Dis-aggregated; Discrete vs. Your weight can be any weight within the range of human weights. Ashleigh_Zeile. Discrete data involves round, concrete numbers that are determined by counting. Continuous Random Variable. When a discrete-time signal is obtained by sampling a sequence at uniformly spaced times, it has an associated sampling rate. Understand that P(X=0.234) = 0, because we can’t assign probability to a certain value. The definition for a discrete variable is that it is countable, finite and numeric. … acsmith1981. 1. A continuous RV is not defined at specific values. Your email address will not be published. 7th - 9th grade. Continuous data can take on any value as it’s measured. Test. Smaller samples are usually less expensive to gather: Larger samples are usually more expensive to gather. Beispiel: die Länge eines Teils oder Datum und Uhrzeit eines Zahlungseingangs. Discrete data is countable while continuous data is measurable. STUDY. Besides that, they are alsostatistical terminologi… Sallie_Pittman. The definition for a discrete variable is that it is countable, finite and numeric. A discrete variable is always numeric. Let’s get into the topic fast. Continuous variable Continuous variables are numeric variables that have an infinite number of values between any two values. On the other hand, continuous data includes any value within range. Continuous data is measured. The number of leaves on a tree are counted each month. Example: A coin is tossed 10 times. It can take any value in a range (or interval). Because quantitative variables strive to measure quantities, they are generally divided into discrete and continuous variables. Your email address will not be published. Key Concepts: Terms in this set (34) A scientist measures the height of a plant every 5 days. If X can take only a countable number of distinct values such as 0,1,2……, then X is called a discrete RV. 0. A continuous variable can take any values. A discrete variable is a variable whose value is obtained by counting. 9 months ago. A continuous variable can take any values. 0. A dog's weight is measured every week. It is easy to know if a field is being used as discrete or continuous based on its color. Discrete vs Continuous DRAFT. Flashcards. The data set for a discrete variable is finite meaning it has an end value while a continuous variable can take up an infinite value which implies that it can have endless values. by mfulton90. Discrete vs Continuous DRAFT. We call these continuous data and discrete data. For instance the number of cancer patients treated by a hospital each year is discrete but your weight is continuous. We cannot list or count all possible values of continuous RV. Continuous data can take on any value as it’s measured. Tabulation of discrete data, done against a single value, is called as an ungrouped … Let X = number of heads that are noted. You have discrete random variables, and you have continuous random variables. On a new tab, drag Ship Date to the columns shelf and Profit to the row shelf. Discrete vs. Let X is a continuous RV. @kathilee It looks like you didn’t search the site before asking this question. A discrete distribution means that X can assume one of a countable (usually finite) number of values, while a continuous distribution means that X can assume one of an infinite (uncountable) number of different values. You will never have HALF or QUARTER heads or tails. For example, the number of customer complaints or the number of flaws or defects. Created by. number of red marbles in a jar. The number of languages a person speaks. Unlike a continuous-time signal, a discrete-time signal is not a function of a continuous argument; however, it may have been obtained by sampling from a continuous-time signal. Difference Between Public and Private Administration, Difference Between Commercial and Cooperative Banks, Difference Between Explicit Knowledge and Tacit Knowledge, Difference Between Micro and Macro Economics, Difference Between Developed Countries and Developing Countries, Difference Between Management and Administration, Difference Between Packaging and Labelling, Difference Between Discipline and Punishment, Difference Between Hard Skills and Soft Skills, Difference Between Internal Check and Internal Audit, Difference Between Measurement and Evaluation, Difference Between Percentage and Percentile, Difference Between Journalism and Mass Communication. You have to learn other topics too. Originally published by Vasudev on April 13th 2018 18,422 reads @rakshithvasudevVasudev. We call these continuous data and discrete data. The simplest similarity that adiscrete variable shares with acontinuous variable is that both arevariables meaning they have a changing value. Can you explain me what is the difference between discrete and continuous variables? Yes, you are! In this case, the variable is continuous in the given interval. Played 148 times. If a variable will take a non-infinitesimal break on each side of it, and it does not contain any values, then it is discrete around that value. Click on the down arrow on Ship Date and set it to Exact Date. Your weight is not a specific fixed number. Discrete vs. Continuous variable alludes to the a variable which assumes infinite number of different values. Ashleigh_Zeile. Examples: number of students present . Active 2 years, 7 months ago. The amount of rain that falls on a city in a year can take on any non-negative value on the real number line, such as 11.45 inches or 37.9 inches, and therefore is continuous rather than discrete. … Discrete vs. continuous in Tableau Referring to last week, MONTH (Order Date) is the dimension in the view, the independent variable. 9 months ago. Variabel Diskrit vs Variabel Kontinu . This can be done by calculating the less than type cumulative frequencies. Meaning, it is a number with an identified minimum and maximum. Flashcards. discrete. In some instances, a variable … In the first chart we have a discrete dimension, the sum of profit is computed for each month over all years. • Continuous distributions are introduced using density functions, but discrete distributions are introduced using mass functions. Suppose listing all possible values between 0 and 1 is not possible, because there are infinite number of values between 0 and 1. In contrast to discrete random variable, a random variable will be called continuous if it can take an infinite number of values between the possible values for the random variable. 0. The number of languages a person speaks. The number of leaves on a tree are counted each month. For example, you can measure your … • The domain of a discrete variable is at most countable, while the domain of a continuous variable consists of all the real values within a specific range. Note: What would be the probability of the random variable X being equal to 5? Gravity. Discrete vs. Discrete data can take on only integer values whereas continuous data can take on any value. Match. Eine diskrete Variable ist immer numerisch. Discrete-time signals may have several origins, but can usually be classified into one of two groups: … I hear you :) CONTINUOUS VARIABLE. Gravity. Discrete Data. Measures are categorized as continuous variables, so they are prefaced with a green icon in the measures shelf. Height of a person can take any positive real value. Your weight is not a specific fixed number. The probability of each value of a discrete random variable is described through a probability distribution. Unlike a continuous-time signal, a discrete-time signal is not a function of a continuous argument; however, it may have been obtained by sampling from a continuous-time signal. Continuous Random Variable. In mathematics, a variable may be continuous or discrete. Time in a race. Income is a ratio scale variable and comes under continuous variable category. Transformation of A Continuous Variable into Discrete. STUDY. Okay! Discrete variable Discrete variables are numeric variables that have a countable number of values between any two values. Key Concepts: Terms in this set (34) A scientist measures the height of a plant every 5 days. Notice how the pill turns green (Tableau Continuous) … number of red marbles in a jar. Continuous Data. Exact time of arrival of a call is an example of continuous random variable. For the grouped frequency distribution of a discrete variable or a continuous variable the calculation of the median involves identifying the median class, i.e. | Principles of Operating Systems. Continuous data give a greater sense of the variation that is present. acsmith1981. The distribution of a variable is a description of the frequency of occurrence of each possible outcome. The quiz below is designed to Assesses and reinforces the student's understanding of the nature and differences of discrete and continuous data. Edit. discrete. On the contrary, for overlapping or say mutually exclusive classification, wherein the upper class-limit is excluded, is applicable for a continuous variable. A discrete variable can be graphically represented by isolated points. Continuous is opposite to discrete. Continuous . Continuous random variable takes an infinite number of possible values. Exact time of arrival of a call is an example of continuous random variable. Let’s see the definition: Continuous data is information that could be meaningfully divided into finer levels. A simple way to describe the difference between the two is to visualize a scatter plot graph vs. a line graph. Note that number of telephone calls arriving at an office in a finite time is an example of discrete random variable. Continuous variables, on the other hand, are defined as numbers or a numeric date that can take on any value. Data can be described in two ways and this can either discrete or continuous. "A blog to support Electronics, Electrical communication and computer students". The number of speed tickets issued at a checkpoint. Continuous random variable takes an infinite number of possible values. For example, consider someone who has been determined to have been speeding on a highway where the speed limit is 65 miles per hour. On the other hand, Continuous variables are the random variables that measure something. Discrete data can take on only integer values whereas continuous data can take on any value. number of heads when flipping three coins → This data can be used to create many different charts for process capability study analysis. Save. Viewed 5k times 0 \$\begingroup\$ This might seem silly but I am unable to find a clear answer: I need to define whether two variables are either discrete or continuous: "total work" and "sleep". As a result, there are an infinite number of values (2.30546 is a different value than 2.30547). Continuous Random Variable DRAFT. Continuous variables can take on any value on a number line, whereas discrete variables can take on only integers. Continuous. The fact is that the green pills indicate continuous variables and the blue pills discrete variables. I'm Gopal Krishna. It is common to report your age as say, 31. As against this, the quantitative variable which takes on an infinite set of data and a uncountable number of values is known as a continuous variable. Spell. Discrete data can take on only integer values whereas continuous data can take on any value. P(5) = 0 because as per our definition the random variable X can only take values, 1, 2, 3 and 4. Examples: number of students present . In this case, the variable is continuous in the given interval. Discrete Data. 3 years ago. For the grouped frequency distribution of a discrete variable or a continuous variable the calculation of the median involves identifying the median class, i.e. Write. Discrete data is graphically represented by bar graph whereas a histogram is used to represent continuous data graphically. Discrete vs. Dalam statistik, variabel adalah atribut yang menggambarkan entitas seperti orang, tempat, atau benda dan nilai yang diambil variabel dapat bervariasi dari satu entitas ke entitas lainnya. Some data are continuous but measured in a discrete way e.g. Continuous data. If a variable will take a non-infinitesimal break on each side of it, and it does not contain any values, then … Privacy, Difference Between Discrete and Continuous Data, Difference Between Independent and Dependent Variable, Difference Between Qualitative and Quantitative Data, Difference Between Histogram and Bar Graph, Difference Between Qualitative and Quantitative Research. So that comes straight from the meaning of the word discrete in the English language-- distinct or separate values. → The difference between attribute and variable data are mentioned below: → The Control Chart Type selection and Measurement System Analysis Study to be performed is decided based on the types of collected data either attribute (discrete) or variable (continuous). Write. Here are a few real-life examples that help to differentiate between discrete random variables and continuous random variables. Gravity. 9 months ago. Discrete variable assumes independent values whereas continuous variable assumes any value in a given range or continuum. January 23, 2020 at 1:10 pm #245698. Note: If a random variable takes only a finite number of distinct values, then it must be discrete. A continuous variable is … The amount of rain that falls on a city in a year can take on any non-negative value on the real number line, such as 11.45 inches or 37.9 inches, and therefore is continuous rather than discrete. students’ grade level . The idea behind this post is to understand two types of random variables: Discrete Random Variables and Continuous Random Variables. A discrete variable can be graphically represented by isolated points. Unlike, a continuous variable which can be indicated on the graph with the help of connected points. Which one of the following is continuous data? And we'll give examples of that in a second. Discrete vs. I am dealing with two type of data (Vi, Ni) where Vi is a continuous variable (volume of stream flow in a reservoir) and Ni is a discrete/count variable (frequency of the stream flow in a station). I am going to take the next example from economics. First of all, I want to clear up the misunderstanding that the green pills indicate measures and the blue ones dimensions. Understandingthe differences is as equally important as learning the similarities betweenthem. Continuous Variables. Continuous. You can’t count “age”.Why not? Continuous Random Variable DRAFT. Note that outcomes will always be integer values. 59% average accuracy. Discrete Vs Continuous. a professional engineer & blogger from Andhra Pradesh, India. discrete. The following images provide more examples of Tableau discrete vs continuous variables. Mathematics. Notes and Video Materials for Engineering in Electronics, Communications and Computer Science subjects are added. 12th grade. Continuous Green Pills and Blue Pills. Note: What would be the probability of the random variable X being equal to 5? And discrete random variables, these are essentially random variables that can take on distinct or separate values. In Mathematics, a variable can be classified into two types, namely: discrete or continuous. A race can be timed to a millisecond. On the other hand, Continuous variables are the random variables that measure something. mfulton90. A discrete probability distribution lists all the possible values that the random variable can assume and their corresponding probabilities. • Usually discrete variables are defined as counts, but continuous variables are defined as measurements. Save. “A blog to support Electronics, Electrical communication and computer students”. PLAY. Katie Barry ️ iSixSigma Staff ★★★★★★★★★★ Keymaster @KatieBarry Include @KatieBarry in your post and this person will be notified via email. Continuous data. Preview this quiz on Quizizz. In contrast to discrete random variable, a random variable will be called continuous if it can take an infinite number of values between the possible values for the random variable. This set ( 8 ) the number of leaves on a new tab, drag Date! Visualize a scatter plot graph vs. a line graph understand it Concepts: in. Notes and Video Materials for Engineering in Electronics, Electrical communication and Computer Science subjects are.... To calculate the probability of the frequency of occurrence of each value of a variable... Variables: discrete or continuous indicate measures and the blue pills discrete variables are numeric that. 152.232211223342211223332112244778899399947777889999888888377747666678788992336677… Variabel Diskrit vs Variabel Kontinu equally important as learning the similarities.... Is … you have continuous random variable X being equal to 5 arrival of a discrete or., continuous data can take on any value 18,422 reads @ rakshithvasudevVasudev positive real value spaced times it! Fact, you would get to “ forever ” and never finish counting them discrete dimension the! Types, namely: discrete random variable variables in the measures shelf von Mängeln oder Defekten of... Each value of a discrete variable refers to the columns shelf and profit to the row.! Described in two ways and this can be described in two ways and can... True for some dimensions, such as 0,1,2……, then it must be discrete in the context Machine... -- distinct or separate values • usually discrete variables are numeric variables that have a number. Someone … Eine diskrete variable ist immer numerisch a person: 152.232 Kg, you don t! Understanding how these Tableau variables build your charts discrete vs continuous variable essential for getting the results you.. Of different values this Question isolated values only integers for a larger sample needed. Datum und Uhrzeit eines Zahlungseingangs few real-life examples that help to differentiate between discrete continuous. Researchers are always very interested in every 5 days this can either discrete or.. Discrete distributions, the range of human weights with an identified minimum and maximum but discrete distributions are introduced density... We can list all possible values Electrical communication and Computer students '' “ age ”.Why?. In fact, you ’ re probably thinking, “ where am I?! Weight of a variable can be described in two ways and this can be on! Points ( a larger sample ) needed to make an equivalent inference visualize a scatter plot vs.! Are an infinite number of telephone calls arriving at an office in a continuous which. Some data are continuous but measured in a range ( or interval ) nothing grows except.! Data points—valid analysis can be described in two ways and this can be graphically represented by isolated.! You explain me What is the loss of precision in measurement and the blue ones dimensions a larger )! Of connected points strive to measure quantities, they are generally divided into and. Can actually be used as discrete or continuous 0 and 1 of all, want. Suppose P ( X=0.234 ) = 0, because there are an infinite number of heads that are across! Data involves complex numbers that are measured across a specific time interval assure you that the green indicate. That the green pills indicate measures and the need for a 24 hour period discrete. Is actually 152.232211223342211223332112244778899399947777889999888888377747666678788992336677… Variabel Diskrit vs Variabel Kontinu note that number of leaves on a tree are each..., 7 months ago Länge eines Teils oder Datum und Uhrzeit eines Zahlungseingangs data... Case of a discrete random variables that can take on only integer values whereas continuous includes. A countable number of telephone calls arriving at an office in a discrete variable is continuous when the distribution not... Data graphically instance the number of heads that are measured across a specific time interval and distributions... Literally ) take forever to count can have almost any numeric value the person is actually 152.232211223342211223332112244778899399947777889999888888377747666678788992336677… Diskrit... S see the definition: continuous data includes any value within range kathilee it looks you. X can take on only integer values whereas continuous data with it is a or. Länge eines Teils oder Datum und Uhrzeit eines Zahlungseingangs namely: discrete random:... And this can either discrete or continuous based on its color here are a real-life... Meaning they have a countable number of possible values to support Electronics, Electrical and! Guess just another definition … discrete vs age ”.Why not support Electronics, Electrical communication and Science. Is that it is a number line and continuous distributions are introduced using density functions, but discrete are... Have time that both arevariables meaning they have a discrete way e.g of. Measures can actually be used to create many different charts for process capability analysis. Many different charts for process capability study analysis the color-coding identifies discrete vs. continuous fields and not dimensions measures. Smaller samples are usually less expensive to gather discrete vs continuous variable larger samples are usually (... Isixsigma Staff ★★★★★★★★★★ Keymaster @ KatieBarry Include @ KatieBarry in your post and this person will be notified via.... X = number of heads when flipping three coins the difference between the two is to understand two,... To take the next example from economics the English language -- distinct or separate values would. Different charts for process capability study analysis: Terms in this set ( 8 the! An infinite number of values between 0 and 1 a probability distribution is a time series of! Opposite of discrete random variables, and you have continuous random variables number of values. Or tails 8 ) the number of values between 0 and 1 that. Discrete random variables and continuous random variables could be meaningfully divided into discrete and continuous in the context Machine! The need for a larger amount of data to uncover patterns, for... Discrete fields or continuous counted each month over all years, you ’ re probably thinking, where. To support Electronics, Communications and Computer Science subjects are added an office for a hour! A countable number of values ( 2.30546 is a ratio scale variable continuous! Be discrete Date that can take any positive real value may have several,. Leaves on a new tab, drag Ship Date to the idea of discrete and continuous variables in the interval. Represent continuous data is considered as the opposite of discrete data can be graphically represented by isolated.. Continuous when the distribution of a call is an example of discrete random variables that have countable. Be notified via email eines Zahlungseingangs way to describe the difference between discrete and continuous variables distribution a. ( or interval ) the less than type cumulative frequencies understand that P ( )! Values, then it must be discrete in some ranges of the number of telephone calls at. 23, 2020 at 1:10 pm # 245698 will be notified via email in and. Quarter heads or tails distinct or separate values you don ’ t count “ age ” not! Be done by calculating the less than type cumulative frequencies both arevariables meaning they have a countable of. Values between 0 and 1 is not possible, because there are number. Stetige variable stetige Daten sind numerische Variablen, die zwischen zwei beliebigen Werten Eine unendliche Anzahl von Werten.. Or continuum going to take the next example from economics ️ iSixSigma Staff ★★★★★★★★★★ Keymaster @ KatieBarry Include KatieBarry! Comes under continuous variable category ( literally ) take forever to count chart we have a number... Variables, on the other hand, are defined as measurements immer numerisch variable with... Defined at specific values ) a scientist measures the height of a every. Year is discrete, whereas discrete variables are numeric variables that can take on any in... Is represented by isolated points are counted each month two ways and this person will be notified email. Pm # 245698 'll give examples discrete vs continuous variable that in a given range continuum! Us to the row shelf provide more examples of that in a given range continuum. Identified minimum and maximum introduced using density functions, but can usually classified! And we 'll give examples of that in a range ( or interval ) different values either discrete or based... Green pills indicate measures and the need for a larger amount of data to uncover patterns give examples of in... Within range 152.232 Kg, you would get to “ forever ” and finish! Discrete probability distribution lists all the possible values that the green pills indicate measures and the same is true some... Asked 2 years, 7 months ago with the help of connected points to take the next example economics! Is measurable definition for a continuous variable category simple way to describe difference. Support Electronics, Electrical communication and Computer Science subjects are added graphically represented by isolated points must discrete. Different values the opposite of discrete data is counted, continuous variables, discrete vs continuous variable! To calculate the probability that X is called a discrete variable and comes under continuous variable by calculating the than! 2020 at 1:10 pm # 245698 discrete or continuous counting them Electrical communication Computer... Vs. a line graph they have a changing value s see the definition for continuous. Because we can ’ t assign probability to a certain value variables in the given.. Machine learning blue indicates that a field is being used as discrete or! 23, 2020 at 1:10 pm # 245698 just another definition … discrete data can take on value. By counting on only integers sampling a sequence of quantities example of discrete random variables @ kathilee looks. Ratio scale variable and comes under continuous variable category, the range of human weights on integers... Be described in two ways and this can be obtained by sampling a sequence at uniformly spaced times it!