Question

Testing the effect of meal type on test performance.Hypothesize that students eating a high protein meal will have higher test performance than students consuming a high carbohydrate meal. Forty students from the researcher’s Introduction to Psychology course were randomly selected from the 250 students in the course for participation in the study. Randomly assigned to either the high protein group or the high carbohydrate group. Each was then given a standardized test over intro psych material one hour after meal consumption (% correct is recorded). The data is below.

Protein              Carbohydrate

95	92
83	73
88	79
80	67
79	82
79	81
97	85
92	83
87	73
89	65
84	72
95	76
86	63
79	60
88	78
69	70
97	75
95	81
90	82
87	69

Mean =   86.95                       Mean = 75.3

S =      7.337538667                         S = 8.137631881

S² =   53.83947368                          S² =  66.22105263

A. What is your computed answer (t, F, or r) ? (What do I do here calculate a t-obs or t-crit? What does that mean/how do I do it? Vassarstats?)

B. What probability level did you choose and why?

C. If you have made an error, would it be a Type I or a Type II error? Explain your answer.

Answer 1

a)

this is independent sample t-test

also this is right-tailed test

b)

we choose alpha = 0.05

c)

type i error - when we reject the null hypothesis when null hypothesis is true

since we reject the null null hypothesis

we could have made type i error