Power plants can emit levels of pollution that can lower air quality. For this reason, it is important to monitor the levels of pollution they produce.

Investigators measured dust emissions, in milligrams per cubic meter, at four power plants. Thirty measurements were taken for each plant. The sample means and standard deviations are presented in the following table.

a. What are the sample sizes n1, n2, n3, n4?

b. What are the sample standard deviations s1, s2, s3, s4?

c. Compute SSTr.

d. Compute SSE.

e. How many degrees of freedom are there for SSTr? For SSE?

f. Compute MSTr and MSE.
g. Compute the value of the test statistic for testing the null hypothesis that the population means are all equal.
h. Can you conclude that there are differences among the mean emission levels? Use the α = 0.05 level of significance.

Transcribed Image Text:

Standard Plant Mean Deviation Sample Size A 211.50 24.85 30 B 214.00 35.26 30 C 211.75 33.53 30 D 236.08 23.09 30