A law requires the average level of CO ( carbon monoxide) in city air to be no more than 9 parts per million (ppm). A government agency is concerned that the city of Rochester is not complying with these standards, that is, that Rochester average level of CO is grater than 9 parts. A random sample of 22 readings within the city yields a mean CO level of 9.7 ppm with a sample standard deviation of 1.17 ppm. Is there sufficient evidence to show that the city of Rochester is not complying with carbon monoxide standards?
a) state the appropriate null and alternative hypotheses; Ho= , Ha=
b) calculate the test statistic.
c) calculate the corresponding p-value ( or range for the p-value)
d) make a statistical decision using level of significance alpha= 0.05. Justify your decision.
e) interpet your decision in the context of the problem.
f) suppose in the above test, the level of significance alpha was decreased. which of the following is correct?
1. The probability of an error of type 1 would be increased
2. The probability of an error of type 2 would be increased
3. The p-value of the test would be decreased
4. The probability of an error of type 2 would be decreased.