In this tutorial I will teach you about doing T tests in Excel 2013.
T test is a statistical term which is used to find out a significance of the result and to check whether the result happened by change. For example. If we want to change the packaging of a product and we would conduct a survey, we will do a T Test to check if the change was effective or not. The larger the value of t, the larger will be the difference in the two samples.
There are 3 types of T tests in excel.
Paired Two Sample for means in Excel. Paired Two Sample for Means is used when you have the sample of your observation paired naturally. This method is often used when you test the same group two times.
Two Sample T test in Excel assuming Equal Variances. This test is done when you have different groups and their variances are same.
Two-sample T test in Excel assuming Unequal variances. This test is done when you have different groups with different variances. If you don’t know the variances, you will use this method.
We will take an Example and the steps to perform T test in excel and interpret the result.
First we will enter the data that will have mean of each subject before and after.
Go to the DATA tab and select Data Analysis tool. If you can’t find the Data Analysis option, Go to the file menu and select options.
Under the data analysis dialogue box, select “t-Test: Paired Two Samples for Means”.
Insert Range of column B in the Variable 1 and Range of column C in the Variable 2.
Enter the hypothesized mean difference in value. In our case we have entered the value 10.
Click OK. This will generate t- Test results in a new sheet.
In order to interpret the result, we will check the t-scores and alpha levels.
First we will compare the alpha level (0.05) to the p-Value. If p-value is smaller than the alpha level, reject your null hypothesis. In our case the p value is 0.00046.
Secondly we will compare the t-critical value in the output t value. If t-value is less than the t-critical, then we will reject the null hypothesis. There are 2 t values here, one tail and two tail. If you are not sure which value to take, always compare the t-value to the two tail t critical value.
For the other two types of tests I-e Two Sample T test in Excel assuming Equal Variances and Two-sample T test in Excel assuming Unequal variances. The steps used are same in excel 2013.