# T-ratio questions. All 3 are multiple choice. Help?

#### psycgal

##### New member
My professor gave us a study guide for our test, and I did ok on most of the problems, but there are a few I am not sure how to do.

1. Susan believes that the d for an experiment she wants to conduct is .50. She will set alpha = .05 one-tailed. Approximately how many subjects will she require for an independent groups t-ratio to have a grater than 90% chance to reject the null hypothesis?

A. 70
B. 80
C. 100
D. 50
E. none of the above

Is there a formula for this one?

2. Mary collects data for five independent groups. She then compares all possible pairs of means using the t-ratio. This procedure will:

A. allow Mary to determine with accuracy which groups are different from one another
B. allow Mary to determine the degree to which the IV and DV are related
C. cause Mary to have an extremely increased risk of committing a Type I error
D. cause Mary to have an extremely decreased risk of committing a Type I error
E. cause Mary to have confidence in the outcome of her results

I think the answer is A, but I'm not positive.

3. A significant t-ratio can be used as evidence for cause and effect if

A. an intact group design was used
B. a true experimental design was used
C. a correlational design was used
D. all of above
E. none of above

I think it is C on this one, but once again, not positive.

#### tkhunny

##### Moderator
Staff member
Do you have a definition of a t-ratio? That might answer all your questions. Let's see what you get for a defintion.