To compare the effectiveness of three different types of phosphorescent coating

Question

To compare the effectiveness of three different types of phosphorescent coating on airplane instrument dials, ten 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, 60.0, 59.3, 66.2, 60.8, 53.1, 65.3, 63.1

Type 2: 58.4, 55.0, 59.8, 52.5, 64.7, 54.9, 54.7, 58.4, 59.9, 55.8

Type 3: 71.3, 66.6, 63.4, 74.7, 75.8, 68.6, 72.9, 67.3, 71.1, 70.7

Test the null hypothesis that there is no difference in the effectiveness of the means of the three coatings at the 0.01 level of significance.

Explanation / Answer

H0: there is no difference in the effectiveness of the means of the three coatings

H1: there is a difference in the effectiveness of the means of the three coatings

alpha:1%

From Excel

Conclusion:

P value=0.000000201

Hence P<0.01 we reject the H0.

Then we conclude that claim is significant

Anova: Single Factor SUMMARY Groups Count Sum Average Variance Type1 10 600.2 60.02 20.71733 Type2 10 574.1 57.41 12.57433 Type3 10 702.4 70.24 14.59156 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 919.5647 2 459.7823 28.80648 2.01E-07 5.488118 Within Groups 430.949 27 15.96107 Total 1350.514 29

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