# Math

posted by
**Amanda**
.

I have a few questions on my homework assignment. I've been sick and I have no idea what I'm doing.

Question 1: Assume the hights of high school bball players are normally distributed. For the boys the mean is 74" with a standard deviation of 4.5" while girl players have a mean height of 70" and a standard deviation of 3". At a mixed 2 on 2 tournament teams are formed by randomaly pairing boys with girls as teammates.

a. On average how much taller do you expect the boy to be

b. What will be the standard deviation of the difference in teammates heights

c. On what fraction of the teams would you expect the girl to be taller than the boy

Question 2: 62% of all purchases are made by credit cards on a typical day you make 20 sales

a. What is the probablity that your 4th customer is the first one who uses a credit card

b. Let X represent the number of coustomers who use a credit card on a typical day. What is the probablity model for X Specify the model (name and parameters), and tell the mean and standard deviation.

c. What is the probability that on a typical day at least 1/2 your customers use a credit card?