Compute test statistic (Independent t-score) Pooled variance S 2 p : Estimated standard error S( M1-M2 ) : Computed Independent t statistic: 2. Make a decision about the null hypothesis and state a...

1. Compute test statistic (Independent t-score)

            Pooled variance S²
_p:

                        Estimated standard error S(_M1-M2)  :

                        Computed Independent t statistic:

2. Make a decision about the null hypothesis and state a conclusion.

      Decision: Are you going to reject the null or fail to reject the null

      Conclusion:  ex. The independent variable did or did not have a significant effect

      Remember: if you reject, there was significance

When people learn a new task, their performance usually improves when they are tested the next day, but only if they get 6 hours sleep (Sticckgold, et al., 2000). The following data demonstrate this phenomenon.  The participants learned a visual discrimination task on one day.  Half of the participants were allowed to have at least 6 hours of sleep and the other half were kept awake all night.

 6 hours sleep No sleep

                                           n =14                                                  n = 14

                                          M = 72                                                M =65

                                          SS = 932                                            SS = 706

Is there a significant difference between the two conditions?   Use a two-tailed test with α = .01.

Remember use the attached t-distribution chart when  obtaining your critical region.