Question

QUESTION- Before applying any inferential tools to the data, always conduct a preliminary analysis to get an idea about the association between your variables. In addition, the results of a statistical analysis are valid only if the appropriate assumptions for the model to be used are valid. The assumptions for the ANOVA are that the data are independent and come from normal populations with equal variances (or standard deviations). In particular:

(a) Obtain the summary statistics (sample size, mean, standard deviation, and variance) for each group. Paste the results into your report. Compare the means of the six groups. Which strategy seems the best? The worst? Compare the standard deviations of the six groups. Does it appear that the assumption of equal variability is satisfied?   

(b) Obtain and paste the side-by-side boxplots into your report. Check the “Use fences to identify outliers” and “Draw boxes horizontally” options. Comment on the shape (symmetric, skewed) of each distribution. Do the plots indicate any differences in the centers and spreads among the six groups? Are there any unusual observations (outliers)? Do the boxplots indicate any clear violation of the assumption of normal populations?

(c) Does it appear that the ANOVA F-test is valid given the results in parts (a) and (b)? Explain briefly.

DATA: ( You will have to paste it to a text editor and format it to be entered into statcrunch - sorry for inconvenience but I could not find another way to post the data)

Strategy Code Score
C 1 45
C 1 53
C 1 72
C 1 55
C 1 67
C 1 53
C 1 66
C 1 54
C 1 53
C 1 67
C 1 60
C 1 64
C 1 69
C 1 52
C 1 74
C 1 58
C 1 53
C 1 66
C 1 66
C 1 71
H 2 79
H 2 95
H 2 81
H 2 74
H 2 68
H 2 84
H 2 78
H 2 77
H 2 85
H 2 72
H 2 86
H 2 71
H 2 67
H 2 77
H 2 83
H 2 73
H 2 76
H 2 86
H 2 83
H 2 75
Q 3 58
Q 3 66
Q 3 67
Q 3 68
Q 3 64
Q 3 57
Q 3 58
Q 3 57
Q 3 75
Q 3 60
Q 3 63
Q 3 55
Q 3 64
Q 3 51
Q 3 60
Q 3 55
Q 3 61
Q 3 63
Q 3 76
Q 3 64
T 4 51
T 4 57
T 4 73
T 4 67
T 4 63
T 4 77
T 4 67
T 4 81
T 4 70
T 4 82
T 4 61
T 4 58
T 4 80
T 4 68
T 4 76
T 4 60
T 4 69
T 4 68
T 4 86
T 4 64
HT 5 78
HT 5 85
HT 5 86
HT 5 92
HT 5 84
HT 5 78
HT 5 79
HT 5 78
HT 5 95
HT 5 81
HT 5 83
HT 5 76
HT 5 83
HT 5 72
HT 5 81
HT 5 70
HT 5 81
HT 5 90
HT 5 95
HT 5 84
QT 6 55
QT 6 80
QT 6 67
QT 6 89
QT 6 90
QT 6 72
QT 6 75
QT 6 61
QT 6 68
QT 6 56
QT 6 63
QT 6 66
QT 6 64
QT 6 65
QT 6 62
QT 6 70
QT 6 83
QT 6 72
QT 6 65
QT 6 73

Group 1: C (control group, only lecture notes and discussion) Group 2: H (control plus weekly homework assignments) Group 3: Q (control plus weekly quizzes) Group 4: T (control plus computer tutorials) Group 5: HT (control plus weekly homework as well as computer tutorials) Group 6: QT (control plus weekly quizzes well as computer tutorials) The following is a description of the first two variables in the data file: Column Description of Variable Variable Nam Strategy Code Score teaching strategy: C, H, Q, T, HT, QT teaching strategy: 1 - C, 2-H, 3-Q.4-T, 5 midterm score (out of 100) HT, 6 QT

Answer 1

iven used yneaM必 2. C how る) mean Hz. 1576

z $2.55 -2, c a7 mean @ G9.8 up Vazl once 잃ud Pevaljon. 8.26 1-as 368 40- 305 T87. 352 T S. 839 QT | 94.80 6.45 6-34 4, 31) 6-77 9.7,3