In a research report on the effect of moisture on a certain kind of composite material, it is reported that in 80% of cases the effect is minimal, in 15% of cases the effect is strong and in the remaining 5% of cases the effect is severe. An experiment tested these clains by subjecting 800 samples of the composite material to moisture.
a) What are the hypotheses needed to test the clain of the report?
b) The results from the sample given below. Complete the expected counts for the hypothesis test.
Effect
Minimal
Strong
Severe
Observed Counts
619
124
57
Expected
c) Calculate the test statistic.
d) What are the degrees of freedom for this test? DF=
e) The experimenter reported a p-value=0.01789. What can you conclude?