Hypothesis Testing We have methods to test our hypothesis and these methods can be categorized into two parts. Parametric Testing: This type of tests make assumptions about the Population parameters and the distributions that the data came from. These types of test includes Student's T tests and ANOVA tests , which assume data is from a normal distribution. Non- parametric Testing: Non - parametric tests are used when there is no or few information available about the population parameters. Z Test: To find test statistics, we can use the below formula. Z test can be done if the below 3 points are satisfied. 1. Sample size should be > 30. 2. Population SD should be known. 3. Variables should be continues. Steps for Z Test: 1. State Null & Alternate Hypothesis. 2. Find t...
Degrees Of Freedom: Degrees of freedom refers to the maximum number of logically independent values in a data sample which have the freedom to vary within. Example: If there is a sample of 3 values {5, x, 15} and the mean of all the values is 10. Now it is easy to say that the value of x would be 10 as the mean of these 3 values is 10. But if 2 values from this sample are not known, say {5, x, y} with same mean 10, then we are now cannot be sure about the exact values of x & y. It could be any values from (10, 15), (15, 10), (5, 20), (20, 5) or even (1, 24). So we cannot determine the exact value of these data x & y. These 2 values has a freedom to vary. But the third value do not have the freedom to change as it has to be some value so that the mean will not change. So this value depends upon all the other values. So the degrees of freedom of this sample data of size 3 is 2. Not only with size 3 sample, a sample with any size we can determine onl...