3. David is a salesman for a local Ford dealership. He is paid a percent of the profit the dealership makes on each car. If the profit is under $800, the commission is 25%. If the profit is at least $800 and less than $1,000, the

commission rate is 27.5% of the profit. If the profit is $1,000 or more, the rate is 30% of the profit. Find the

difference between the commission paid if David sells a car for a $1,000 profit and the commission paid if he

sells a car for a $799 profit?

.25x,

p(x) = 3.275x,

x < $800

$800 < x < $1000

x $1000

.30x,

(20 points) a bank has been receiving complaints from real estate agents that their customers have been waiting too long for mortgage confirmations. the bank prides itself on its mortgage application process and decides to investigate the claims. the bank manager takes a random sample of 20 customers whose mortgage applications have been processed in the last 6 months and finds the following wait times (in days): 5, 7, 22, 4, 12, 9, 9, 14, 3, 6, 5, 15, 10, 17, 12, 10, 9, 4, 10, 13 assume that the random variable x measures the number of days a customer waits for mortgage processing at this bank, and assume that x is normally distributed. 2a. find the sample mean of this data (x ě…). 2b. find the sample variance of x. find the variance of x ě…. for (c), (d), and (e), use the appropriate t-distribution 2c. find the 90% confidence interval for the population mean (îľ). 2d. test the hypothesis that îľ is equal to 7 at the 95% confidence level. (should you do a one-tailed or two-tailed test here? ) 2e. what is the approximate p-value of this hypothesis?