Students t-test

Question 1

when do you use an unpaired, or paired t-test

Answer 1

• paired: data that has been collected from the same individual both times
• unpaired: data that has been collected from 2 different sets of people

Question 2

what is the formula for unpaired t-test

Answer 2

GIVEN
- but basically subtract the means
- divide by the square root of
- each standard deviation squared over the number of individuals added

• DIFFERENT FORMULA FOR PAIRED

Question 3

what is the null hypothesis in a t-test

Answer 3

there is no significant difference between the means of the 2 data sets

Question 4

what is the degrees of freedom in t-tests

Answer 4

• unpaired: (n1+n2) - 2
• paired: (n)-1

Question 5

what does your critical value tell you

Answer 5

• if the value you got is GREATER than the critical value, then you can reject the null hypothesis
• and you can be 95% confident that the difference is significant and NOT due to chance
• vice versa