One year, the mean age of an inmate on death row was 39.7 years. A sociologist w
ID: 3324028 • Letter: O
Question
One year, the mean age of an inmate on death row was 39.7 years. A sociologist wondered whether the mean age of a death-row inmate has changed since then. She randomly selects 32 death-row inmates and finds that their mean age is 37.9, with a standard deviation of 9.4. Construct a 95% confidence interval about the mean age, what does the interval imply? Click the icon to view the table of critical t-values. Choose the correct hypotheses. (Type integers or decimals. Do not round.) Construct a 95% confidence interval about the mean age. Lower Bound:Upper Bound: (Round to two decimal places as needed.) What does the interval imply? OA. Since the mean age from the earlier year is not contained in the interval, there is sufficient evidence to conclude that the mean age had changed O B. Since the mean age from the earlier year is contained in the interval, there is not s cient evidence to conclude that the mean age had changed ° C. Since the mean age from the earlier year is not contained in the interval, there is not sufficient evidence to conclude that the mean age had changed. 0 D. Since the mean age from the earlier year is contained in the interval, there is sufficient evidence to conclude that the mean age had changed.Explanation / Answer
Pop. mean = 39.7
n = 32
Sample. mean = 37.9
Stdev = 9.4
A 95% CI is given by:
Xbar +/- Z*SE
= 39.7 +/- 1.96*9.4/sqrt(32)
Lower =36.44 to Upper bound = 42.96
The Sample mean of 37.9 is within this range bound.
The interval applies that :
B.Since the mean age from the earlier year is contained in the interval, there is not suficient evidence to conclude that the mean age had changed.
Hence, B is correct
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