WEBVTT Kind: captions; language: en-us NOTE Treffsikkerhet: 85% (HØY) 00:00:00.399 --> 00:00:08.200 In this video, we will talk about variables. Variables are very important in statistics and not just 00:00:08.200 --> 00:00:15.300 in statistics, variables are a fundamental concepts in every science. We Define variables. We 00:00:15.300 --> 00:00:21.850 measure variables. We analyze variables. Usually, with statistics. And then, we draw conclusions 00:00:21.850 --> 00:00:28.800 relating to our original questions, which also have to be posed in the form of variables. NOTE Treffsikkerhet: 78% (HØY) 00:00:29.300 --> 00:00:38.300 So what are variables? Well, variables can be thought of as containers that can take different 00:00:38.300 --> 00:00:45.200 values. So, in other words, you can start by thinking of variables a variable, as being a box, and 00:00:45.200 --> 00:00:52.200 you can put some things in it, but not everything. So, that's the important thing. If the variable 00:00:52.200 --> 00:00:59.500 is a box that can admit only certain kinds of things, what you can put in, are the values of the NOTE Treffsikkerhet: 91% (HØY) 00:00:59.500 --> 00:01:09.300 variable. So it can take different values. And the variable itself is defined by having a name, and 00:01:09.300 --> 00:01:15.450 then also the types and ranges of the values that can be associated with it. NOTE Treffsikkerhet: 91% (HØY) 00:01:15.450 --> 00:01:23.300 Examples of variables are things like sex height, birth order birth year and these are frequently 00:01:23.300 --> 00:01:32.800 used variables in research that has to do with people. So in other words, the box must have a name. NOTE Treffsikkerhet: 91% (HØY) 00:01:32.900 --> 00:01:42.600 And it also needs to have a definition of what kinds of values can go in. For example, if the name 00:01:42.600 --> 00:01:52.100 is sex, then possible values, might be female and male. So there's only two words that can go into 00:01:52.100 --> 00:01:57.800 that box one for each person that is measured on this variable. NOTE Treffsikkerhet: 91% (HØY) 00:01:59.300 --> 00:02:07.250 If the variable is height, then the values that can go in the Box are very different. In this case. 00:02:07.250 --> 00:02:14.300 they would be numbers and they can be the number of centimeters or it can be a number of meters and 00:02:14.300 --> 00:02:19.950 that's part of the definition of the variable. It's very important. So we don't get confused between 00:02:19.950 --> 00:02:23.900 1.6 and 160. NOTE Treffsikkerhet: 87% (HØY) 00:02:26.300 --> 00:02:32.200 For another variable that might be called the birth year. The possible values that can go into the 00:02:32.200 --> 00:02:40.600 box is the year in which the person was born. So variables of these shorts NOTE Treffsikkerhet: 91% (HØY) 00:02:40.600 --> 00:02:49.800 must refer to some entity, that's the entity being measured. And we usually think of entities 00:02:49.800 --> 00:02:56.200 related to the variables of the examples as being persons, but they could have been animals, indeed. 00:02:56.200 --> 00:03:01.700 They could have been trees. And there's also different kinds of entities that can be studied and we 00:03:01.700 --> 00:03:06.700 can define and measure variables on them, depending on the kind of research that were interested in. 00:03:06.700 --> 00:03:11.500 So other people may study countries or species or buildings or whatever. NOTE Treffsikkerhet: 91% (HØY) 00:03:11.500 --> 00:03:16.600 But there's always an entity on which the variable is measured. NOTE Treffsikkerhet: 91% (HØY) 00:03:16.600 --> 00:03:24.600 It needs very important that we need to define and be aware of the properties of the values that go 00:03:24.600 --> 00:03:30.200 into the variable and these depend on what kind of variable this is. NOTE Treffsikkerhet: 82% (HØY) 00:03:32.100 --> 00:03:39.000 The kinds of things that we need to define, are the possible values there. If there are any units of 00:03:39.000 --> 00:03:46.500 measurement, how we derive those values and what scale, those values are measured on. We will talk 00:03:46.500 --> 00:03:53.700 about scale in a different video, but about the other things, we can talk a little bit more when it 00:03:53.700 --> 00:03:59.400 comes to the definition of the content of a variable starting with the values. And we've already 00:03:59.400 --> 00:04:02.050 seen two different kinds of NOTE Treffsikkerhet: 71% (MEDIUM) 00:04:02.050 --> 00:04:08.800 values that can go in one is words as in the variable sex. We actually use the words male or 00:04:08.800 --> 00:04:17.100 female. We could have used the letters m or F. Or you could use K and M. If we were using the 00:04:17.100 --> 00:04:26.300 Norwegian initials we can use codes are going to use one or two for the two Sexes or in some kinds 00:04:26.300 --> 00:04:32.000 of research we might want to have more labels permissible and off just to. So NOTE Treffsikkerhet: 91% (HØY) 00:04:32.000 --> 00:04:34.600 we need to define all those things. NOTE Treffsikkerhet: 86% (HØY) 00:04:34.600 --> 00:04:42.900 What is a range of values that can go in? Is there a limited set? And it specifically, which one is 00:04:42.900 --> 00:04:49.500 it? Which words go in there? It's very confusing and it's going to lead to a lot of mistakes. If we 00:04:49.500 --> 00:04:56.000 don't specifically limit the range to the minimum number of values that can code what they're 00:04:56.000 --> 00:05:04.000 interested in. So if one person is using labels male and female, and another person is using kvinnne and 00:05:04.000 --> 00:05:04.250 mann NOTE Treffsikkerhet: 85% (HØY) 00:05:04.250 --> 00:05:08.800 And then this is going to be very confusing because you're going to have four labels in our sex 00:05:08.800 --> 00:05:15.300 variable and this is not going to work when it tried to analyze. So that specific definition of what 00:05:15.300 --> 00:05:21.700 is the permissible set of values is very important. The other type of values is numbers. NOTE Treffsikkerhet: 87% (HØY) 00:05:21.700 --> 00:05:28.750 So we need to be aware of what kinds of numbers can go into the box. Is there a range of numbers? 00:05:28.750 --> 00:05:35.200 are all the numbers limited to be, for example, between 0 & 1 or between zero and hundred? Can it be 00:05:35.200 --> 00:05:43.200 any number? Do they have to be integers or can they have decimal places? Are they units 00:05:43.200 --> 00:05:48.200 associated with these numbers`? when they're actual numbers they're usually, they have a meaning 00:05:48.200 --> 00:05:51.500 that's expressed via some unit. So is it centimeters? NOTE Treffsikkerhet: 89% (HØY) 00:05:51.500 --> 00:05:57.800 Is it meters? Is it kilograms? Is it seconds? Is it years? Here's what exactly are the numbers? This is a 00:05:57.800 --> 00:06:06.300 very important part of the definition. Then there is the issue of how we get those values, whether 00:06:06.300 --> 00:06:09.100 they are words or numbers. NOTE Treffsikkerhet: 84% (HØY) 00:06:09.100 --> 00:06:15.600 Do you use a questionnaire? Do we ask people? How tall are you or do you use an instrument? Like do 00:06:15.600 --> 00:06:23.100 we have a measuring tape or some other device to measure people's heights ourselves? Do we look 00:06:23.100 --> 00:06:28.700 up their heights in some sort of database? So the mode of obtaining, the value can be very 00:06:28.700 --> 00:06:36.800 important. And finally, there is this the issue of measuring scale which defines what we can do with 00:06:36.800 --> 00:06:38.950 these values and we're going to talk about that. NOTE Treffsikkerhet: 91% (HØY) 00:06:38.950 --> 00:06:41.300 In the next video. NOTE Treffsikkerhet: 85% (HØY) 00:06:43.600 --> 00:06:50.700 So is it final definition when we talk about variables and this might come as a bit of a surprise 00:06:50.700 --> 00:07:02.300 is that measurement is the action of assigning a value to a variable. Measuring isn't only when you 00:07:02.300 --> 00:07:09.600 use a measuring tape to find out what a person's height is it is also measurement in this sense when 00:07:09.600 --> 00:07:13.200 we ask someone how tall are you and we write NOTE Treffsikkerhet: 75% (MEDIUM) 00:07:13.200 --> 00:07:15.850 down the answer that we get. NOTE Treffsikkerhet: 79% (HØY) 00:07:15.850 --> 00:07:24.100 Anyway that we can use to assign a value to a variable is called a measurement.