Two-sample T-test
p-value less than the significance value, p is significant, p less representative of the mean difference between the two samples is larger, it is assumed that the original two variables negative relationship exists, the smaller the p value the stronger the relationship
Variation on behalf of a difference
The total variation
Variation within the group
The value of each variable minus the mean of the successive respective groups
Variation between groups
4 and 8, respectively, the mean of the two groups is the total average of 6