# Question: Based on tests of the Chevrolet Cobalt engineers have found

Based on tests of the Chevrolet Cobalt, engineers have found that the miles per gallon in highway driving are normally distributed, with a mean of 32 miles per gallon and a standard deviation of 3.5 miles per gallon.

(a) What is the probability that a randomly selected Cobalt gets more than 34 miles per gallon?

(b) Ten Cobalts are randomly selected and the miles per gallon for each car are recorded. What is the probability that the mean miles per gallon exceeds 34 miles per gallon?

(c) Twenty Cobalts are randomly selected and the miles per gallon for each car are recorded. What is the probability that the mean miles per gallon exceeds 34 miles per gallon? Would this result be unusual?

(a) What is the probability that a randomly selected Cobalt gets more than 34 miles per gallon?

(b) Ten Cobalts are randomly selected and the miles per gallon for each car are recorded. What is the probability that the mean miles per gallon exceeds 34 miles per gallon?

(c) Twenty Cobalts are randomly selected and the miles per gallon for each car are recorded. What is the probability that the mean miles per gallon exceeds 34 miles per gallon? Would this result be unusual?

## Answer to relevant Questions

The shape of the distribution of the time required to get an oil change at a 10-minute oil-change facility is unknown. However, records indicate that the mean time for an oil change is 11.4 minutes, and the standard ...According to Crown ATM Network, the mean ATM withdrawal is $67. Assume that the standard deviation for withdrawals is $35. (a) Do you think the variable “ATM withdrawal” is normally distributed? If not, what shape would ...n = 500, p = 0.4 According to a study done by Wakeﬁeld Research, the proportion of Americans who can order a meal in a foreign language is 0.47. (b) In the sample obtained in part (a), what is the probability the proportion of Americans ...In this section, we assumed that the sample size was less than 5% of the size of the population. When sampling without replacement from a ﬁnite population in which n > 0.05N, the standard deviation of the distribution of ...Post your question