In: Statistics and Probability
Three systems were compared to see if they have similar output
in terms of products per hour. Determine if there is evidence of a
difference in mean output in the three systems. Use a 0.05 level of
significance.
System 1 | System 2 | System 3 |
---|---|---|
35 | 39 | 62 |
35 | 32 | 46 |
45 | 35 | 61 |
58 | 36 | 62 |
40 | 33 | 34 |
61 | 35 | 46 |
44 | 38 | 49 |
53 | 31 | 54 |
56 | 32 | 40 |
43 | 31 | 50 |
34 | 61 | |
35 | 41 | |
34 | 41 | |
35 | 61 | |
39 | 59 | |
57 | ||
47 | ||
43 | ||
50 | ||
62 |
1.) What is the correct hypotheses statements?
2.)What is the F-statistic for the one-way ANOVA? Round to 4 decimal places.
3.)What is the p-value of the F statistic? Enter your answer with 4 decimal places.
4.)Should the null hypothesis be rejected or not? And are post-hoc tests needed?
Solution: We can use the excel ANOVA: Single Factor data analysis tool to find the answer to the given questions. The excel output is given below:
Anova: Single Factor | ||||||
SUMMARY | ||||||
Groups | Count | Sum | Average | Variance | ||
System 1 | 10 | 470 | 47 | 88.88888889 | ||
System 2 | 15 | 519 | 34.6 | 6.828571429 | ||
System 3 | 20 | 1026 | 51.3 | 79.8 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Between Groups | 2453.977778 | 2 | 1226.988889 | 21.36724991 | 0.0000 | 3.2199 |
Within Groups | 2411.8 | 42 | 57.42380952 | |||
Total | 4865.777778 | 44 |
1.) What is the correct hypotheses statements?
Answer: The null and alternative hypotheses are:
2.)What is the F-statistic for the one-way ANOVA? Round to 4 decimal places.
Answer:
3.)What is the p-value of the F statistic? Enter your answer with 4 decimal places.
Answer:
4.)Should the null hypothesis be rejected or not? And are post-hoc tests needed?
Answer: Since the p-value is less than the significance level, we, therefore, reject the null hypothesis and posthoc tests are required to determine which groups are statistically significant.