Question

A study of reading comprehension in children compared three methods of instruction. The three methods of instruction are called Basal, DRTA, and Strategies. As is common in such studies, several pretest variables were measured before any instruction was given. One purpose of the pretest was to see if the three groups of children were similar in their comprehension skills. The READING data set described in the Data Appendix gives two pretest measures that were used in this study. Use one-way ANOVA to analyze these data and write a summary of your results.

Reading 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

Use Excel and enter the data as given in question:

Then use the following steps:

Click on Data Tab --> Data Analysis --> Anova: Single Factor -->In input range, select all the 5 column data containing pre1, pre2, post1, post2 and post3 columns --> Choose 'Columns' in Grouped by option --> Tick the labels checkbox -->Select output range and specify a cell where result should be displayed ---> Click ok

The result is:

Anova: Single Factor
SUMMARY
Groups	Count	Sum	Average	Variance
pre1	66	646	9.787879	9.123543
pre2	66	337	5.106061	4.89627
post1	66	533	8.075758	11.51725
post2	66	443	6.712121	6.94662
post3	66	2905	44.01515	44.13823

ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups	71493.16	4	17873.29	1166.33	2.6E-191	2.399432
Within Groups	4980.424	325	15.32438
Total	76473.59	329

As the p-value = 2.6 E^-191 << 0.05, we reject H₀ (the null hypothesis) and conclude that the results are significant. Hence, there is a significant difference between the three groups of children in terms of their comprehension skills.