A study of the effect of television commercials on 12-year-old children measured their attention span, in seconds. Clothes Food Toys
27 44 61
22 49 64
46 37 57
35 56 48
28 47 63
31 42 53
17 34 48
31 43 58
20 57 47
47 51
44 51
54
1. Find the values of mean and standard deviation.
2. Is there a difference in mean attention span of the children for various commercials?
3. Are there significance differences between pair of means?