A consumer group has determined that the distribution of life spans for gas ranges (stoves) has a mean of 15.0 years and a standard deviation of 4.2 years. The distribution of life spans for electric ranges has a mean of 13.4 years and a standard deviation of 3.7 years. Both distributions are moderately skewed to the right. Suppose we take a simple random sample of 35 gas ranges and a second SRS of 40 electric ranges. Which of the following best describes the sampling distribution of x0-xg, the difference in mean life span of gas ranges and electric ranges?
A. Mean = 1.6 years, standard deviation = 7.9 years, shape: moderately right-skewed.
B. Mean = 1.6 years, standard deviation = 0.92 years, shape: moderately right skewed.
C. Mean = 1.6 years, standard deviation = 0.92 years, shape: approximately Normal.
D. Mean = 1.6 years, standard deviation = 0.40 years, shape: approximately Normal.
E. Mean = 1.6 years, standard deviation = 0.40 years, shape: moderately right skewed.
the Correct Answer is: C
Mean = 1.6 years, standard deviation = 0.92 years, shape: approximately Normal.
The Solution
