In a one factor between groups design having four groups, there ...

[kwoodring]

In a one factor between groups design having four groups, there are six possible two-group comparisons that should be made at the end of the experiment. If alpha is set at .05, and the experimenter uses the ANOVA to compare the group means, the experiment wise probability of a Type I error is _____.
 
  a. .05 c. .60
  b. .30 d. impossible to calculate

Question 2

In a one factor between groups design having four groups, there are six possible two-group comparisons that should be made at the end of the experiment. If alpha is set at .05, and the experimenter uses separate t tests to compare the group means, the experiment wise probability of a Type I error is _____.
 
  a. .05
  b. .30
  c. .60
  d. impossible to determine without more information

[kkenney]

Answer to Question 1

A
ANOVA is a statistical technique that maintains the experiment wise probability of a Type I error at alpha.

Answer to Question 2

C
For every comparison made, alpha (here .05) must be added to the experiment wise probability of at Type I error. Here there are 6 comparisons that must be made; therefore 6(.05) or .30 is the experiment wise probability of a Type I error.