Question

Assuming that a computer has been used to compute a P-value = 0.01635, what can we conclude about the following situation? A simple random sample of 50 speeds (in mph) is obtained from cars traveling on a section of I-10 through Tallahassee. The sample has a mean of 72.3 mph and a standard deviation of 7.4 mph. Use a 0.05 significance level to test the claim that the mean speed of all cars is greater than the posted speed limit of 70 mph.

Answer 1

Explanation:

From the information given, we would write the hypothesis.

For the null hypothesis,

H0 : µ = 70

For the null hypothesis,

Ha : µ > 70

This is a right tailed test because of the symbol of greater than.

The decision rule is to reject the null hypothesis if the level of significance is greater than the p value and accept the null hypothesis if the level of significance is lesser than the p value.

Therefore, since the significance level, 0.05 > p value, 0.01635, then we would reject the null hypothesis. There is enough evidence that the mean speed of all cars is greater than the posted speed limit of 70 mph.