In: Statistics and Probability
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 |
| 20 | 33 | 55 |
| 24 | 43 | 53 |
| 35 | 34 | 40 |
| 35 | 50 | 44 |
| 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.)
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3.) Is there a difference in the mean attention span of the children for the various commercials?
The hypothesis of identical means can definitely REJECTED/ NOT REJECTED be.There is A DİFFERENCE /NO DİFFERENCE in the mean attention span.
ANSWERS:
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Ans 1) Excel Output:
| ANOVA: Single Factor | ||||||
| SUMMARY | ||||||
| Groups | Count | Sum | Average | Variance | ||
| Clothes | 9 | 241 | 26.77778 | 45.94444 | ||
| Food | 12 | 528 | 44 | 59.09091 | ||
| Toys | 11 | 563 | 51.18182 | 41.16364 | ||
| ANOVA | ||||||
| Source of Variation | SS | df | MS | F | P-value | F crit |
| Between Groups | 3056.3 | 2 | 1528.2 | 31.00 | 6.27E-08 | 3.33 |
| Within Groups | 1429.2 | 29 | 49.3 | |||
| Total | 4485.5 | 31 |
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Ans 2)
Descriptive statistics for clothes, foods, toys :
| Level | N | Mean | StDev |
| Clothes | 9 | 26.778 | 6.778 |
| Food | 12 | 44.000 | 7.687 |
| Toys | 11 | 51.182 | 6.416 |
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Ans 3)
According to the descriptive statistics table,
Yes, there a difference in the mean attention span of the children for the various commercials.
Here the F-cal value is 31 which is greater than F-critical 3.33 which means our null hypothesis is rejected and there is a difference in the mean attention span.
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