Question

To compare the effectiveness of three different types of phosphorescent coatings on airplane instrument dials, eight dials each are coated with the three types Then the dials are illuminated by an ultraviolet light. and the following are the number of minutes each glowed after the light source was shut off Type 1: 52.9, 62.1, 57.4, 50.0, 59.3, 61.2,60.8, 53.1 Type 2: 58.4, 55.0, 598, 62.5, 64.7, 59.9, 54.7, 58.4 Type 3: 713,666. 63.4, 64.7,75.8,656, 729,67.3 Test the null hypothesis that there is no difference in the effectiveness of the three coatings at the 0.01 level of significance

Answer 1

$H_0:\mu _1=\mu _2=\mu _3$

$H_a:$ at least one mean is different

Significance level:$\alpha =0.01$

Since the P value is less than the significance level, we can reject the null hypothesis.

Hence we have evidence that there is a difference in the effectiveness of the three coatings