OK, to tell you the truth, z is almost never used to test hypotheses because we usually don't know the value of the population standard deviation.So, if we don't know we have to use our sample SD (s) in the error term.

We can quickly calculate a t-test using the Type-A data above.All we need is the SD and n of your sample.

Estimated Standard Error of mean formula:s_M=s /n What is the s for your Type-A data? ____

13. Compute the t-test statistic:t=(M - ) / s_M

a. The mean difference between sample (M) and population () = _____________

b. Error term: estimated SE of mean:s_M=s /nsample SEM =

c. Divide to get t-value for this hypothesis test t =

14. a. Degrees of freedom (df) = n-1 df = ___________

b . Find the Critical t-values (Consult table, use =.05, two-tailed and your df): ______________

15. Decision time again:Do you reject the Null? (yes or no?) ____________

Write a conclusion for your class's Type-A personality study including APA report of a t-test: ________________________________________________________________________________