6. Let the random variable X represent the profit made on a randomly selected day by a certain store. Assume that X is approximately Normal with mean $360 and standard deviation $50. The most profitable 1% of days have a profit of at least how many dollars? (a) $244 (b) $296 c) $370 (d) $424 (e) $476 7. Which of the following is a true statement? (a) The binomial setting requires that there are only two possible outcomes for each trial, while the geometric setting permits more than two outcomes. (b) A geometric random variable takes on integer values from 1 to n. (c) If X is a geometric random variable and the probability of success is 0.85, then the probability distribution of X will be skewed left, since 0.85 is closer to 1 than to 0. (d) An important difference between binomial and geometric random variables is that there is a fixed number of trials in a geometric setting, and the number of trials varies in a binomial setting. (e) The distribution of every binomial random variable is skewed right. Use the following for problems 8 and 9. The number of DVDs rented daily at DVD rental machine has a mean of 140 with a standard deviation of 22. 8. Select two days at random and find the sum in the number of DVDs rented on the two days. What are the mean and standard deviation of the sum in the number of DVDs rented? (a) Mean = 280, Standard Deviation = 44 (b) Mean = 280, Standard Deviation = 31 (c) Mean = 0, Standard Deviation = 31 (d) Mean = 140, Standard Deviation = 42 (e) Mean = 140, Standard Deviation = 31 9. The cost of the electricity to keep the DVD rental machine on is $2.50 per day. Each DVD rental increases the electricity cost by $0.05. What are the mean and standard deviation of the electricity cost per day? (a) Mean = $7.00, Standard Deviation = $1.10 (b) Mean = $9.50, Standard Deviation = $2.20 (c) Mean = $9.50, Standard Deviation = $1.10 d) Mean = $7.00, Standard Deviation = $2.20 (e) Mean = $8.00, Standard Deviation = $1.10 10. A random variable X has a probability distribution as follows: X 0 2 3 P(X 3.7 5.1 2.9 3.3 C C Where C is a positive constant. The probability P(X $ 2) is equal to a. .22 b. .59 c. .78 d. .82 e. 1