t is necessary for an automobile producer to estimate the number of miles per ga
ID: 3072947 • Letter: T
Question
t is necessary for an automobile producer to estimate the number of miles per gallon achieved by its cars. Suppose that the sample mean for a random sample of 150 cars is 30.2 miles and assume the standard deviation is 3.6 miles. Now suppose the car producer wants to test the hypothesis that , the mean number of miles per gallon, is 30.5 against the alternative hypothesis that it is not 30.5. Conduct a test using =.05 by giving the following:
(a) positive critical z score:
(b) negative critical z score:
(c) test statistic :
The final conclustion is
A. There is not sufficient evidence to reject the null hypothesis that =30.5.
B. We can reject the null hypothesis that =30.5 and accept that 30.5.
Explanation / Answer
The statistical software output for this problem is:
One sample Z summary hypothesis test:
: Mean of population
H0 : = 30.5
HA : 30.5
Standard deviation = 3.6
Hypothesis test results:
Hence,
a) Positive critical z score = 1.96
b) Negative critical z score = -1.96
c) Test statistic = -1.0206
Final conclusion: There is not sufficient evidence to reject the null hypothesis that =30.5. Option A is correct.
Mean n Sample Mean Std. Err. Z-Stat P-value 150 30.2 0.29393877 -1.0206207 0.3074Related Questions
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