Opre homework 2

question 7

Question 7 The results of a survey of 800 married couples and the number of children they had is shown below Number of Children Probability 0 0.1 0.3 2 0.4 3 0.2 What is the expected value of the number of children in a family? O a. 1 O b. 1.7 O c. 2 O d. 1.5Question 9 The weights of items produced by a company are normally distributed with a mean of 5 ounces and a standard deviation of 0.2 ounces. What is the minimum weight of the heaviest 9.85% of all items produced? If you want to use Excel to solve this question, download this blank sheet: Blank sheet.xIsx O a. 9.850 O b. 1.290 O c. 4.742 O d. 5.258Question 13 If Z is a standard normal random variable, find the value z for which, the area between 0 and z is 0.25: If you want to use Excel to solve this question, download this blank sheet: Blank sheet.xIsx O a. 0.674 O b.-0.599 O c. 0.599 O d.-0.674Question 8 Two events, A and B, are mutually exclusive and each has a nonzero probability. If event A is known to occur, the probability of the occurrence of event B is O a. one O b. any positive value O c. zero O d. any value between 0 to 1Question 10 If the mean of a normal distribution is negative O a. the standard deviation must also be negative O b. the variance must also be negative O c. a mistake has been made in the computations because the mean of a normal distribution cannot be negative O d. None of the alternative answers is correctQuestion 11 Consider four events (A, B,C,D) for which we know: P(AC) = 0.95 P(B) = 0.2 P(C) = 0.25 P(D) = 0.08 P(A U B) = 0.25 P(D C) = 0.1 Are events A and B mutually exclusive? O a. Yes, because p ( A n B) = 0 O b. No, because p (An B) + 0 O c. Yes, because P(A|B) = 0 O d. Both (A) and (C)Question 12 Which of the following variables cannot have a Discrete probability distribution? O a. The number of bacteria found in a cubic yard of soil. O b. The length of a movie O c. The number of customers arriving at a gas station on Christmas day O d. The number of telephone calls received by a switchboard in a specified time period