SOLUTION: For the following hypothesis test, A) state the null and alternative hypotheses, B) determine the critical value(s) that define the rejection region, C) calculate the value of the

Question 959313: For the following hypothesis test, A) state the null and alternative hypotheses, B) determine the critical value(s) that define the rejection region, C) calculate the value of the test statistic, D) make the decision to reject the null hypothesis or not, E) state a full conclusion, a sentence in the context of the given problem.
A simple random sample of 40 recorded speeds (in mph) is obtained from cars in a certain parking lot. The sample has a mean of 67.2 mph and a standard deviation of 6.2 mph. Use a 5% level of significance to test the claim that the mean speed of the cars in the lot is less than 70 mph.
Could someone please tell me if the following answers are correct.
A) Ho: mean = 70; H1: mean < 70
B) Critical t = -1.685
C) -2.9
D) Reject Ho
E) The mean speed of cars in a certain parking lot is significantly less than 70mph
Please let me know - thanks
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!

A simple random sample of 40 recorded speeds (in mph) is obtained from cars in a certain parking lot. The sample has a mean of 67.2 mph and a standard deviation of 6.2 mph. Use a 5% level of significance to test the claim that the mean speed of the cars in the lot is less than 70 mph.
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A) state the null and alternative hypotheses, B) determine the critical value(s) that define the rejection region, C) calculate the value of the test statistic, D) make the decision to reject the null hypothesis or not, E) state a full conclusion, a sentence in the context of the given problem.
Could someone please tell me if the following answers are correct.
A) Ho: mean = 70;
H1: mean < 70
B) Critical t = -1.685
I see you have chosen to use a t-value because it is a means test.
C) -2.9
D) Reject Ho
E) The mean speed of cars in a certain parking lot is significantly less than 70mph
Please let me know - thanks
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I checked each part of your work. Looks good to me.
Cheers,
Stan H.
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