Question

1) For a normal distribution curve with a mean of 7 and a standard deviation of 4, which of the following ranges of the variable will define an area under the curve corresponding to a probability of approximately 34%?

a) from 7 to 11 b)from –1 to 15 c) from 5 to 9 d) from 3 to 11

2) The average age of vehicles registered in the United States is 96 months. Assume the population is normally distributed with a standard deviation of 15 months. Find the probability that the mean age of a sample of 36 vehicles is between 98 and 100 months?

a) 15.7% b)44.5% c)6.4% d)28.8%

Answer 1