 Assalamu alaikum, this is Saima Ghazal and we are doing statistics in psychology. Last time we talked about what is statistics, why statistics is important in psychology and how we can use it in psychology. We learned that statistics is a science of learning from numbers. Statistics is all about data, statistics is all about measurement. We talked about statistics in psychology is a one tool that makes your subject a science because science is the most important pillar that talks about measurement. Like in our real sciences, there is measurement, there are solids and masses, we can measure them. But psychology, amazingly, is a science because we can measure attributes, we can measure personality, cognition, intelligence, all the things that are hidden in ourselves but we can measure them through research or statistics. So if it is a question of measurement, so what we need to measure exactly in statistics, today we will talk about it. So what to measure, we measure variables and what are the variables that change or anything that changes. So we can talk about anything, variables, your age, height, your gender, your socioeconomic status, your personality, anything like we can talk about anything that changes, that's in the variable. And the opposite we talk about is constant, constant means that things that don't change. So in statistics when we do testing hypothesis, we have variables, we have research questions, we have hypotheses in which we have variables and they have a proposed relationship. So if I say first, I want to study, how many hours do I have to study and what is the number of hours we spent in studying in the final GPA, maybe in the state, there are two variables. Now we can talk about constant and variable, if I just say first I want to study across all students on campus, if I am studying boys and girls both, maybe gender is a variable. But if I am just taking females or collecting data from girls only, maybe then gender is not a variable because I have constant the data of girls. So, variable means anything that changes or the different values we can acquire. You have heard about independent variable and dependent variable. So, independent variable is used mostly in our experimental research design and we will talk about them also. But we are looking at the effect of independent variable on another variable or in other words, we manipulate it or we look at the changing of the variable. So, variable is thought to be cause of some effect and this term is usually used in experimental research to denote a variable. For example, smoking damages health. There are two variables in this. Smoking and health. So, what we are changing? We are looking at smoking. Some are doing less, some are not. Some are doing more. So, this is a variable that is changing. So, my independent variable is smoking. Because I want to see the effect of this or I want to see the relationship of this with another variable which is health. Health also will be different. I can see by using any question. So, health is also a variable but that is actually dependent variable. Because I am looking at the effect of smoking or the relationship of smoking with health. Similarly, we can have tons of examples from our everyday life where we can talk about variables in psychology. You just talk about any attribute, any kind of characteristic, any personality trait, anything. And then you can formulate the hypothesis and identify independent variable. Another example could be screen time increases attention problems in children. So, screen time is a variable in which we are looking at the effect of less or more. So, in the case of children, attention problems or focusing, screen time is a variable which is an independent variable. And we are looking at the effect of that in children's attention problems. So, dependent variable, we have already talked about a variable which we are manipulating or changing. And we are looking at the effect of that in another variable. Variable where we are checking the effect is on. That is called dependent variable. So, if I read it, the variable that is observed and measured to obtain scores in the dependent. Usually, we are looking at the changes of the independent variable on your dependent variable. In the last example, we talked about smoking or health. So, health, of course, is a dependent variable. So, if we want to look at the effect of screen time or relationship on attention problems in children, then attention problem would be a dependent variable. Mostly, if you want to identify, then usually your outcome variable is your dependent variable. It is part of your own self, which we measure what changes have come in your independent variable. One more thing that we measure, we are talking about what to measure. So, variables are also discreet and continuous. Discreet variable means that any variable which can take on whole values and whole numbers only. First, number of chairs in a class, 24 chairs or 20 chairs, number of family members. I cannot say that these are 24.5 chairs or 3.5 family members. So, any variable that can take on only whole numbers and can be expressed in whole numbers called discreet variables and if we talk about this, then continuous variable like continuous variable. Just as the name says, it can take on any value along the scale. Just as your height, it can be 5.8, 3, 2, 4, 5. It can take on any value along the scale and there are no continuous numbers or gaps. So, there are many examples of continuous variables like your height, your weight, your GPA. So, any value that can take on decimal values that can lie anywhere along the scale is called a continuous variable. Similarly, when we talk about variables, we talk about independent, dependent variable. We talk about extraneous variables such as variables which my researcher is not interested in but they actually are affecting your dependent variable. Just as we talked about smoking and health, I am measuring smoking and health only but there are so many other variables that are actually affecting my health. For example, my lifestyle, for example, my exercise habits, my diet, my family members, my social support, my peer, so many things are at play. They are affecting, so they are called extraneous variables. Types of extraneous variables, maybe we will talk more about when we will be talking about experimental design in next lectures and also confounding variables. Confounding variables are also a type of extraneous variable. But the difference is that a confounding variable is actually affecting your dependent variable in a systematic way. Just as the change is happening in your independent variable similarly, your dependent variable is also affecting your true confounding variable. For example, if I look at what is the effect of music performance and maybe I am checking the shift workers the morning shift or the evening shift or the night shift will change in a systematic way because in the morning you are more fresh. In the afternoon you have done a lot of work and then at night there will be a difference. It is also an extraneous variable but it is more systematic in a way when it is affecting your dependent variable. We will talk in detail about this one also when we will talk about experimental research design. In this tutorial or module we discussed what to measure, we will measure variables and their independent, dependent, discrete continues extraneous and confounding.