Question
Suppose an editor of a publishing company claims that the mean time to write a textbook is at most 15 months. We do not know the variance of population. However, a sample of 16 textbook authors is randomly selected and it is found that the mean time taken by them to write a textbook was 18.3 months and s 36 months. Find the critical value and test the editor's claim using a 0.025 level of significance. 17.63. Reject H0 o 17.91. Accept Ho o 18.20. Reject Ho 18.38. Accept Ho QUESTION 4 Suppose the mean salary for physicians in the United States is believed to be more than 8185,650. A sample of 30 physicians revealed a mean selary sd $2,700.000. Find the critical value and test the uul
Explanation / Answer
Below are the null and alternate hypothesis
H0: mu <= 15
Ha: mu > 15
Test statistic,
t = (18.3 - 15)/(6/sqrt(16))
t = 2.2
df = 15
p-value = 0.0219
Critical value of t = 2.1314
Using central limit theorem,
xbar = mean + t*sigma
xbar = 15 + 2.1314*6/sqrt(16)
xbar = 18.1971
Option C, 18.20, Reject H0