Question 1.1. The mean life expectancy of a certain type of light bulb is 895 hours with a standard deviation of 18 hours. What is the approximate standard deviation of the sampling distribution of the mean for all samples with n = 40?
(Points : 3)
2.85 h

2.22 h

0.60 h

0.45 h

Question

Question 1.1. The mean life expectancy of a certain type of light bulb is 895 hours with a standard deviation of 18 hours. What is the approximate standard deviation of the sampling distribution of the mean for all samples with n = 40?
(Points : 3)
       2.85 h

       2.22 h

       0.60 h

       0.45 h

anonymous · Answer

Question 2.2. If 52% of the customers at a certain grocery store regularly use coupons, what is the approximate standard deviation of the sampling distribution of the proportion for samples of size 240?
(Points : 3)
       2.1%

       3.2%

       4.7%

       10.4%



Question 3.3. A researcher takes a simple random sample of 98 homes in a city and finds that the mean square footage is 1543 with a standard deviation of 177 square feet. What is the 90% confidence interval for the mean square footage of all the homes in that city?
(Points : 3)
       (1508 ft2, 1578 ft2)

       (1514 ft2, 1572 ft2)

       (1525 ft2, 1561 ft2)

       (1530 ft2, 1556 ft2)