MAT 120 - Midterm Review Name Identify the population and the sample. 1) When 1094 American households were surveyed, it was found that 67% of them owned two cars. Identify whether the statement describes inferential statistics or descriptive statistics. 2) The average age of the students in a statistics class is 19 years. Identify the data set's level of measurement. 3) temperatures of 12 selected refrigerators 4) marriage status (married, single, or divorced) of the faculty at the University of Colorado 5) the ratings of a movie ranging from "poor" to "good" to "excellent" 6) number of milligrams of tar in 85 cigarettes Determine whether the data are qualitative or quantitative. 7) the number of seats in a movie theater 8) the colors of automobiles on a used car lot Identify the sampling technique used. 9) A researcher randomly selects and interviews fifty male and fifty female teachers. 10) To ensure customer satisfaction, every 20th phone call received by customer service will be monitored. 11) To avoid working late, the quality control manager inspects the last 50 items produced that day. 12) A researcher randomly selected 25 of the nation's middle schools and interviewed all of the teachers at each school. 13) A lobbyist for a major airspace firm assigns a number to each legislator and then uses a computer to randomly generate ten numbers. The lobbyist contacts the legislators corresponding to these numbers. 14) Find the mean, median, and mode of the following numbers: 73 76 69 73 66 74 73 67 68 71 15) A student receives test scores of 62, 83, and 91. The student's final exam score is 88 and homework score is 76. Each test is worth 20% of the final grade, the final exam is 25% of the final grade, and the homework grade is 15% of the final grade. What is the student's mean score in the class? 1.tst
Use the given frequency distribution to find the (a) class width. (b) class midpoints of the first class. (c) class boundaries of the first class. 16) Phone Calls (per day) Class Frequency, f 8-11 18 12-15 23 16-19 38 20-23 47 24-27 32 Use the grouped data formulas to find the indicated mean or standard deviation. 17) For the following data set, approximate both the sample mean and the sample standard deviation. Phone calls (per day) Frequency 8-11 18 12-15 23 16-19 38 20-23 47 24-27 32 The Highway Patrol, using radar, checked the speeds (in mph) of 30 passing motorists at a checkpoint. The results are listed below. 44 38 41 50 36 36 43 42 49 48 35 40 37 41 43 50 45 45 39 38 50 41 47 36 35 40 42 43 48 33 18) Construct a frequency histogram using six classes. Then describe the shape of the curve. 19) For the stem-and-leaf plot below, find the 5 number summary, range, and interquartile range (IQR). Key: 2 7 = 27 1 2 2 3 3 4 3 5 2 3 4 4 5 6 7 7 7 8 8 9 9 9 0 1 1 2 3 4 4 5 6 6 6 7 8 8 9 0 1 20) For the mathematics part of the SAT the mean is 514 with a standard deviation of 113, and for the mathematics part of the ACT the mean is 20.6 with a standard deviation of 5.1. Bob scores a 660 on the SAT and a 27 on the ACT. Use z-scores to determine on which test he performed better.
21) The mean IQ score of adults is 100, with a standard deviation of 15. Use the Empirical Rule to find the percentage of adults with scores between 70 and 130. (Assume the data set has a bell-shaped distribution.) 22) The mean SAT verbal score is 428, with a standard deviation of 97. Use the Empirical Rule to determine what percent of the scores lie between 428 and 525. (Assume the data set has a bell-shaped distribution.) 23) A study of 1000 randomly selected flights of a major airline showed that 769 of the flights arrived on time. What is the probability of a flight arriving on time? 24) A single six-sided die is rolled. Find the probability of rolling a number less than 3. 25) If one card is drawn from a standard deck of 52 playing cards, what is the probability of drawing an ace? 26) The data in the table represent the number of consumer complaints against major U.S. airlines. If one complaint from the table is randomly selected, find the probability that it was not filed against Continental Airlines. (Round to three decimal places.) Airline Number of Complaints United 287 Northwest 256 Continental 202 27) The random variable x represents the number of cars per household in a town of 1000 households. Find the probability of randomly selecting a household that has less than two cars. Cars Households 0 125 1 428 2 256 3 108 4 83 28) A group of students were asked if they carry a credit card. The responses are listed in the table. Class Credit Card Carrier Not a Credit Card Carrier Total Freshman 45 15 60 Sophomore 32 8 40 Total 77 23 100 If a student is selected at random, find the probability that he or she owns a credit card given that the student is a freshman. Round your answer to three decimal places. 29) Classify the events as dependent or independent. Event A: A red candy is selected from a package with 30 colored candies and eaten. Event B: A blue candy is selected from the same package and eaten.
30) Find the probability of getting four consecutive aces when four cards are drawn without replacement from a standard deck of 52 playing cards. 31) You are dealt two cards successively without replacement from a standard deck of 52 playing cards. Find the probability that the first card is a two and the second card is a ten. Round your answer to three decimal places. 32) Decide if the events A and B are mutually exclusive or not mutually exclusive. A die is rolled. A: The result is an odd number. B: The result is an even number. 33) Decide if the events A and B are mutually exclusive or not mutually exclusive. A card is drawn from a standard deck of 52 playing cards. A: The result is a club. B: The result is a king. 34) The table lists the smoking habits of a group of college students. Sex Non-smoker Regular Smoker Heavy Smoker Total Man 135 51 5 191 Woman 187 21 12 220 Total 322 72 17 411 If a student is chosen at random, find the probability of getting someone who is a regular or heavy smoker. Round your answer to three decimal places. 35) The table lists the smoking habits of a group of college students. Sex Non-smoker Regular Smoker Heavy Smoker Total Man 135 70 5 210 Woman 187 21 15 223 Total 322 91 20 433 If a student is chosen at random, find the probability of getting someone who is a man or a non-smoker. Round your answer to three decimal places. 36) A card is drawn from a standard deck of 52 playing cards. Find the probability that the card is an ace or a king. 37) A card is drawn from a standard deck of 52 playing cards. Find the probability that the card is an ace or a black card. 38) The access code to a house's security system consists of eight digits. How many different codes are available if each digit can be repeated? 39) If a couple plans to have nine children, how many gender sequences are possible?
40) There are 19 students participating in a spelling bee. How many ways can the students who go first, second, and third be chosen? 41) How many ways can a jury of eight men and eight women be selected from twelve men and ten women? 42) In the California State lottery, you must select six numbers from fifty-two numbers to win the big prize. The numbers do not have to be in a particular order. What is the probability that you will win the big prize if you buy one ticket? 43) State whether the variable is discrete or continuous. The number of cups of coffee sold in a cafeteria during lunch 44) State whether the variable is discrete or continuous. The temperature in degrees Fahrenheit on July 4th in Juneau, Alaska 45) The random variable x represents the number of credit cards that adults have along with the corresponding probabilities. Graph the probability distribution. Then find the mean and standard deviation. x P(x) 0 0.07 1 0.68 2 0.21 3 0.03 4 0.01 46) At a raffle, 10,000 tickets are sold at $5 each for three prizes valued at $4,800, $1,200, and $400. What is the expected value of one ticket? 47) In a recent survey, 80% of the community favored building a police substation in their neighborhood. If 15 citizens are chosen, what is the mean number favoring the substation? 48) In a recent survey, 73% of the community favored building a police substation in their neighborhood. If 14 citizens are chosen, find the probability that exactly 8 of them favor the building of the police substation. 49) The probability that a woman between the ages of 25 and 29 will never marry is 40%. In a random survey of 10 women in this age group, what is the probability that two or fewer will never marry? 50) A recent survey found that 70% of all adults over 50 wear glasses for driving. In a random sample of 10 adults over 50, what is the probability that at least six wear glasses?