Sales of a well-known restaurant in Windsor, on a random weekend, follow a normal distribution with a mean of $4100, and a standard deviation of $1500. Total Expenses also follow a normal distribution with a mean of $3000, and a standard deviation of $900. Assume Sales and Expenses are independent random variables. Let Profit = Sales - Expenses. The standard deviation of Profit on a random weekend, in dollars, is:

a. 1200

b. 1749

c. 3060000

d. 1440000

An orthodontist group has three financingpackages, and each has a different service charge. He estimates that about 35% of the patients use the first plan which has a service charge of $100; 27% use the second plan which has a service charge of $200, and remaining use the third plan which has a service charge of $300. The standard deviation of the service charge, in dollars, is:

a. 7291

b. 85.39

c. 80.64

d. 6509.56

A large collection of accounting errors follow a normal distribution with a mean of 0, and a standard deviationof 1.The IQR for this data is:

a. 2.134

b. 1.943

c. 2.314

d. 1.349