Question

A study of reading comprehension in children compared three methods of instruction. The three methods of instruction are called Basal, DRTA, and Strategies. Basal is the traditional method of teaching, while DRTA and Strategies are two innovative methods based on similar theoretical considerations. The READING data set includes three response variables (posttests) that the new methods were designed to improve. Analyze The Posttest 2 score using ANOVA.
a. What is the response variable?

Method of instruction Traditional teaching method     Innovative teaching method Posttest 2 score

b. What is the explanatory variable?

Traditional teaching method Innovative teaching method     Method of instruction Posttest 2 score

c. What alternative hypothesis are you testing?

At least one population mean is different The sample means for all three methods of instruction are equal     The population means for all three methods of instruction are equal At least one sample mean is different

d. What are the mean scores for Posttest 2 for each of the three methods of instruction? Round your answers to 2 decimal places.
Basal 4
DRTA 5
Strategies 6

e. What are the values of F and P for the ANOVA? Round your answers to 2 decimal places.
F 7
p-value 8

f. What is your conclusion?

Fail to reject the null hypothesis. There is not sufficient evidence to support a difference in means. Reject the null hypothesis. We can conclude that at least one mean is different.    

g. Compare Posttest 2 scores for the Basal and DRTA methods using a t-test of means (assuming unequal variances). What is your conclusion?

Fail to reject the null hypothesis. There is not sufficient evidence to conclude that mean scores for Basal and DRTA methods are different. A t-test is not appropriate because the F-test was not significant.     Reject the null hypothesis. We can conclude that mean scores for Basal and DRTA methods are different.

h. Compare Posttest 2 scores for the Basal and Strategies methods using a t-test of means (assuming unequal variances). What is your conclusion?

Fail to reject the null hypothesis. There is not sufficient evidence to conclude that mean scores for Basal and Strategies methods are different.
Reject the null hypothesis. We can conclude that mean scores for Basal and Strategies methods are different.     A t-test is not appropriate because the F-test was not significant.

i. Compare Posttest 2 scores for the DRTA and Strategies methods using a t-test of means (assuming unequal variances). What is your conclusion?

A t-test is not appropriate because the F-test was not significant. Reject the null hypothesis. We can conclude that mean scores for DRTA and Strategies methods are different.     Fail to reject the null hypothesis. There is not sufficient evidence to conclude that mean scores for DRTA and strategies methods are different.

data:

subject group   pre1    pre2    post1   post2   post3
1       B       4       3       5       4       41
2       B       6       5       9       5       41
3       B       9       4       5       3       43
4       B       12      6       8       5       46
5       B       16      5       10      9       46
6       B       15      13      9       8       45
7       B       14      8       12      5       45
8       B       12      7       5       5       32
9       B       12      3       8       7       33
10      B       8       8       7       7       39
11      B       13      7       12      4       42
12      B       9       2       4       4       45
13      B       12      5       4       6       39
14      B       12      2       8       8       44
15      B       12      2       6       4       36
16      B       10      10      9       10      49
17      B       8       5       3       3       40
18      B       12      5       5       5       35
19      B       11      3       4       5       36
20      B       8       4       2       3       40
21      B       7       3       5       4       54
22      B       9       6       7       8       32
23      D       7       2       7       6       31
24      D       7       6       5       6       40
25      D       12      4       13      3       48
26      D       10      1       5       7       30
27      D       16      8       14      7       42
28      D       15      7       14      6       48
29      D       9       6       10      9       49
30      D       8       7       13      5       53
31      D       13      7       12      7       48
32      D       12      8       11      6       43
33      D       7       6       8       5       55
34      D       6       2       7       0       55
35      D       8       4       10      6       57
36      D       9       6       8       6       53
37      D       9       4       8       7       37
38      D       8       4       10      11      50
39      D       9       5       12      6       54
40      D       13      6       10      6       41
41      D       10      2       11      6       49
42      D       8       6       7       8       47
43      D       8       5       8       8       49
44      D       10      6       12      6       49
45      S       11      7       11      12      53
46      S       7       6       4       8       47
47      S       4       6       4       10      41
48      S       7       2       4       4       49
49      S       7       6       3       9       43
50      S       6       5       8       5       45
51      S       11      5       12      8       50
52      S       14      6       14      12      48
53      S       13      6       12      11      49
54      S       9       5       7       11      42
55      S       12      3       5       10      38
56      S       13      9       9       9       42
57      S       4       6       1       10      34
58      S       13      8       13      1       48
59      S       6       4       7       9       51
60      S       12      3       5       13      33
61      S       6       6       7       9       44
62      S       11      4       11      7       48
63      S       14      4       15      7       49
64      S       8       2       9       5       33
65      S       5       3       6       8       45
66      S       8       3       4       6       42

Answer 1