Question

A study on students drinking habits asks a random sample of 60 male UF students how many alcoholic beverages they have consumed in the past week. The sample reveals an average of 5.84 alcoholic drinks, with a standard deviation of 4.98. Construct a 95% confidence interval for the true average number of alcoholic drinks all UF male students have in a one week period.

A. (4.78, 6.90)

B. (0, 15.60)

C.(4.58, 7.10)

D. (-3.92, 15.60)

Answer 1

A. (4.78, 6.90)

Explanation:

Using the following formulas the lower and upper limits of the Interval are calculated

Lower limit = mean - (standard deviation /√sample size)* Zr

Upper limit = mean + (standard deviation /√sample size)* Zr

Zr depends on confidence interval and can be found in a z table

Zr for 90% = 1.645

then

Lower limit = 5.84 - (4.98 /√60)* 1.645 = 4.78

Upper limit = 5.84 + (4.98 /√60)* 1.645 = 6.90