Question

For #8 on page 469, put the data in Excel with the correct format for ANOVA. See the page 22 on ANOVA 1 slide. Then do Levene test and write down the p-value of Levene test with 3 decimal points.

Answer 1

The Data

Detergent 1	Detergent 2	Detergent 3
84	78	87
79	74	80
87	81	91
85	86	77
94	86	78
89	89	79
89	69	77
83	79	78

The tests

Method

Null hypothesis   All variances are equal
Alternative hypothesis   At least one variance is different
Significance level   α = 0.05

95% Bonferroni Confidence Intervals for Standard Deviations

Sample N   StDev CI
Detergent 1 8 4.55914   (2.24810, 13.1943)
Detergent 2 8   6.71353   (3.48027, 18.4809)
Detergent 3 8   5.22186   (1.40284, 27.7382)
Individual confidence level = 98.3333%

Tests

Method Test Statistic   P-Value
Multiple comparisons   — 0.566
Levene 0.64 0.537

Note: Used Minitab for calcutation