79. What is a Distribution.

Before we can talk about testing we have to learn what a distribution is. And then this lesson will do just that. In statistics when we use the term distribution we usually mean a probability distribution good examples or the normal distribution the binomial distribution and the uniform distribution. All right let’s start with the definition. A distribution is a function that shows the possible values for a variable and how often they occur. Think about a fair die. It has 6 sides numbered from 1 to 6. We roll the die. What is the probability of getting one. It is 1 out of 6. So 1 6 right. Easy. What is the probability of getting 2. Once again one sixth. The same holds for 3 4 5 and 6. We have an equal chance of getting each of the 6 outcomes. Now what is the probability of getting a 7. It is impossible to get a 7 when rolling a single die. Therefore the probability is zero.