Question

A study of the effect of television commercials on 12-year-old children measured their attention span, in seconds. The commercials were for clothes, food, and toys.

  

Clothes	Food	Toys
26	45	60
21	48	51
43	43	43
35	53	54
28	47	63
31	42	53
17	34	48
31	43	58
20	57	47
	47	51
	44	51
	54

  

1. Complete the ANOVA table. Use 0.05 significance level. (Round the SS and MS values to 1 decimal place, and F value to 2 decimal places. Leave no cells blank — be certain to enter "0" wherever required. Round the df values to nearest whole number.)

2. Find the values of mean and standard deviation. (Round the mean and standard deviation values to 3 decimal places.)

3. Is there a difference in the mean attention span of the children for the various commercials?

4. Are there significant differences between pairs of means?

Answer 1

Run Anova single factor analysis in excel to answer the above questions

Go to data tab --> choose data analysis --> Anova single factor

Complete the ANOVA table. Use 0.05 significance level. (Round the SS and MS values to 1 decimal place, and F value to 2 decimal places. Leave no cells blank — be certain to enter "0" wherever required. Round the df values to nearest whole number.

ANOVA
Source of Variation	SS	df	MS	F
Between Groups	3182.0	2	1591.0	35.56
Within Groups	1297.5	29	44.7
Total	4479.5	31

Find the values of mean and standard deviation. (Round the mean and standard deviation values to 3 decimal places.)

SUMMARY
Groups	Count	Sum	Average	Variance	Standard deviation
Clothes	9	252	28.000	66.25	8.139
Food	12	557	46.417	38.27	6.186
Toys	11	579	52.636	34.65	5.887

The square root of the variance is called the Standard Deviation σ.

Is there a difference in the mean attention span of the children for the various commercials? Are there significant differences between pairs of means?

p-value is less than 0.05

If the p-value is less than 0.05, we reject the null hypothesis that there's no difference between the means and conclude that a significant difference does exist