# Tagged Questions

2answers
66 views

### Statistical test for normalised data

Thank you all (@Drew75 and @Nathan Calverley) for your replies, and thank you @Michael Lew for sharing your paper. I will provide additional details regarding my experiment. I am working with culture ...
0answers
48 views

### t-test on two variance calculations

I have survey data that was recorded in a many different towns. I want to see for which variables is the data significantly more or less variable within towns than across all towns. Currently, I'm ...
2answers
5k views

### How do I interpret the results from the F-test in excel

I have a fairly simple question regarding the interpretation of the F-test in Microsoft Excel. Let't say these are the results of my F-test: I am now wondering how to interpret it in order to ...
4answers
1k views

### Can I do a t test if I have little to no variance in one group?

I have 4 groups that I am comparing to a criterion. In one of my groups, all the participants answered the same on every item, i.e. there is no variance. How do I deal with that in my ANOVA? Also, ...
1answer
6k views

### Why Levene test of equality of variances rather than F ratio?

SPSS uses the Levene test to evaluate homogeneity of variances in the independent group t-test procedure. Why is the Levene test better than a simple F ratio of the ratio of the variances of the ...
1answer
291 views

### Choosing N when doing t-tests on bootstrapped samples

Specifically the Welch's T-Test, but probably any T-Test, requires a value for Mean, Variance and N to be used to calculate the T-statistic and the degrees of freedom. I am concerned about these ...
1answer
524 views

### Why does a paired t-test (when appropriate) result in better variance?

I didn't quite get the Wikipedia explanation here: http://en.wikipedia.org/wiki/Paired_difference_test#Use_in_reducing_variance I agree that both the unpaired and paired means are the same...then I ...
6answers
2k views

### When conducting a t-test why would one prefer to assume (or test for) equal variances rather than always use a Welch approximation of the df?

It seems like when the assumption of homogeneity of variance is met that the results from a Welch adjusted t-test and a standard t-test are approximately the same. Why not simply always use the Welch ...