Question

Statistics exercises

Friedman’s K/One-way repeated measures ANOVA

1. Suppose you are interested in learning if practice on the ACT improves test scores. You sample a random group of 10 people and ask them to take the ACT 1 time per week for 3 consecutive weeks. Use the data below to determine if practice improves test scores.

Participant	Test 1	Test 2	Test 3
1	18	23	24
2	20	22	26
3	21	24	23
4	19	25	28
5	20	21	23
6	19	22	25
7	20	20	20
8	21	23	25
9	28	27	29
10	25	27	26

1. State the hypotheses

2. Select an alpha level and one- or two-tailed

3. Select and compute the appropriate statistic

4. Report in APA style the df and p-value.

5. Accept or reject the null and draw an inference if one is warranted.

Answer 1

H0: the ACT not improves test scores.

H1: the ACT improves test scores.

It is one tailed test

From the given data

Anova Table					Alpha =	0.05
Source	df	SS	MSS	Var. Ratio F	F-critic	P-Value
B/w groups	2	73.267	36.633	13.9114	3.5546	0.00022
Within Group	27	196.2	7.2667
i) B/w Subject	9	148.8
ii) Error	18	47.4	2.633
Total:	29	269.4667

Test Statistic F = 3.5546

since P-value for two tailed = 0.00022 and P-value for 1-tailed is 0.0001 < alpha 0.05 so we reject H0

Thus we conclude that  the ACT improves test scores.