Find the mean of the distribution shown

Chapter 5 Test

Question 1 Find the mean of the distribution shown. X 1 2

P(X) 0.32 0.68 a. 0.50 b. 1.50 c. 1.17 d. 1.68

Question 2 Give the variance of the following distribution? X 0 1 2 3 4

P(X) 0.20 0.35 0.10 0.25 0.10 a. 1.83 b. 1.31 c. 1.25 d. 1.71

Question 3 Find the mean of the distribution shown below.

X 2 3 4

P(X) 0.36 0.40 0.24 a. 1.20 b. 2.88 c. 2.40 d. 2.76

Question 4 Find the mean of the distribution shown. X 4 6

P(X) 0.36 0.64 a. 1.64 b. 4.00 c. 5.28 d. 6.00

Question 5 What is the standard deviation of the following probability distribution? X 0 2 4 6 8

P(X) 0.20 0.05 0.35 0.25 0.15 a. 2.6 b. 4.7 c. 5.4 d. 3.9

Question 6 Find the mean of the distribution shown below. X -4 -2 0 2

P(X) 0.44 0.24 0.23 0.09 a. –2.06 b. 0.25 c. 2.42 d. –1.00

Question 7 Give the mean of the following probability distribution? X 2 3 4 5

P(X) 0.50 0.25 0.15 0.10 a. 0.25 b. 1.28 c. 2.85 d. 3.50

Question 8 Find the mean of the distribution shown. X -3 -2 -1 0

P(X) 0.27 0.24 0.38 0.11 a. –1.98 b. –1.67 c. –2.19 d. 2.19

Question 9 The number of cartoons watched on Saturday mornings by students in Mrs. Kelly's first grade class is shown below. Number of cartoons watched X 0 1 2 3 4 5

Probability P(X) 0.15 0.20 0.30 0.10 0.20 0.05 What is the mean of the data? a. 1.37 b. 2.15 c. 1.89 d. 1.18

Question 10 The number of cartoons watched on Saturday mornings by students in Mrs. Kelly's first grade class is shown below. Number of cartoons watched X 0 1 2 3 4 5 Probability P(X) 0.15 0.20 0.30 0.10 0.20 0.05 Give the standard deviation for the probability distribution. a.1.46 b. 2.25 c. 1.89 d. 1.18

Question 11 Find the mean of the distribution shown below. X 2 3 4

P(X) 0.35 0.24 0.41 a. 1.56 b. 2.06 c. 2.56 d. 3.06

Question 12 If a gambler rolls two dice and gets a sum of 10, he wins $10, and if he gets a sum of three, he wins $20. The cost to play the game is $5. What is the expectation of this game? a. $3.06 b. –$2.78 c. –$3.06 d.$2.78

Question 13 In a large bag of marbles, 20% of them are red. A child chooses 4 marbles from this bag. If the child chooses the marbles at random, what is the chance that the child gets exactly three red marbles? a. 0.026 b. 0.102 c. 0.154 d. 0.032

Question 14 A coin is tossed five times. Find the probability of getting exactly three heads. a. 0.125 b. 0.156 c. 0.800 d. 0.313

Question 15 If a student randomly guesses at 20 multiple-choice questions, find the probability that the student gets exactly four correct. Each question has four possible choices. a. 0.190 b. 0.162 c. 0.085 d. 0.218

Question 16 A pet supplier has a stock of parakeets of which 20% are blue parakeets. A pet store orders 3 parakeets from this supplier. If the supplier selects the parakeets at random, what is the chance that the pet store gets exactly one blue parakeet? a. 0.128 b. 0.384 c. 0.096 d. 0.024

Question 17 A jewelry supplier has a supply of earrings which are 40% platinum. A store owner orders five sets of earrings from the supplier. If the supplier selects the pairs of earrings at random, what is the chance that the jewelry store gets exactly two sets of platinum pairs? a. 0.4320 b. 0.2880 c. 0.3456 d. 0.1920

Question 18 A student takes a 6 question multiple choice quiz with 4 choices for each question. If the student guesses at random on each question, what is the probability that the student gets exactly 4 questions correct? a. 0.008 b. 0.025 c. 0.033 d. 0.066

Question 19 A computer store has 75 printers of which 20 are laser printers and 55 are ink jet printers. If a group of 10 printers is chosen at random from the store, find the mean and variance of the number of ink jet printers. a. Mean = 7.3, Variance = 2.0 b. Mean = 7.3, Variance = 1.4 c. Mean = 2.7, Variance = 2.0 d. Mean = 2.7, Variance = 1.4

Question 20 A coin is tossed 72 times. Find the standard deviation for the number of heads that will be tossed. a. 36 b. 18 c. 4.24 d. 6.78

Question 21 A multiple choice quiz consists of 50 questions, each with 4 possible answers. Find the mean for the number of correct answers, if a student guesses on each question. a. 25.0 b. 12.5 c. 4.0 d. 46.0

Question 22 A die is rolled 360 times. Find the standard deviation of the number of times a 3 will be rolled. a. 21.3 b. 50 c. 7.1 d. 5.9

Question 23 A certain large manufacturing facility produces 20,000 parts each week. The manager of the facility estimates that about 1% of the parts they make are defective. What is the variance for the number of defective parts made each week? a. 200 b. 198 c. 14.1 d.138

Question 24 A university has 10,000 students of which 35% are male and 65% are female. If a class of 30 students is chosen at random from the university population, find the mean and variance of the number of male students. a. Mean = 19.5, Variance = 2.6 b. Mean = 10.5, Variance = 2.6 c. Mean = 19.5, Variance = 6.8 d. Mean = 10.5, Variance = 6.8

Question 25 The failure rate for taking the bar exam in Philadelphia is 41%. If 375 people take the bar exam, what is the mean for the number of failures? a. 138.1 b. 221.3 c. 90.7 d.153.8