front 1 Determine whether the given description corresponds to an observational study or an experiment. A clinic gives a drug to a group of ten patients and a placebo to another group of ten patients to find out if the drug has an effect on the patients' illness. | back 1 Experiment |
front 2 Determine whether the given description corresponds to an observational study or an experiment. A T.V. show's executives raised the fee for commercials following a report that the show received a "No. 1" rating in a survey of viewers. | back 2 Observational study |
front 3 Determine whether the given description corresponds to an observational study or an experiment. A quality control specialist compares the output from a machine with a new lubricant to the output of machines with the old lubricant. | back 3 Experiment |
front 4 Determine whether the given description corresponds to an observational study or an experiment. A T.V. show's executives commissioned a study to gauge the impact of the show's ratings on the sales of its advertisers. | back 4 Observational study |
front 5 You are dealt two cards successively (without replacement) from a shuffled deck of 52 playing cards. Find the probability that the first card is a King and the second card is a queen. Express your answer as a simplified fraction. | back 5 4/663 (4/52) x (4/51) |
front 6 A bag contains 2 red marbles, 3 blue marbles, and 7 green marbles. If a marble is randomly selected from the bag, what is the probability that it is blue? | back 6 1/4 (3blue / 12total) |
front 7 The table above describes the smoking habits of a group of asthma sufferers. If two different people are randomly selected from the 948 subjects, find the probability that they are both heavy smokers. Round to six decimal places. | back 7 0.007218 (81/948) x (80/947) |
front 8 Find the probability of correctly answering the first 5 questions on a multiple choice test if random guesses are made and each question has 6 possible answers. | back 8 1/7776 (1) x (1/6)^{5} |
front 9 The data set represents the income levels of the members of a country club. Find the probability that a randomly selected member earns at least $97,000. Round your answers to the nearest tenth. | back 9 0.7 1 – (6/20) |
front 10 In one town, 79% of adults have health insurance. What is the probability that 4 adults selected at random from the town all have health insurance? Round to the nearest thousandth if necessary. | back 10 0.39 (0.79)^{4} |
front 11 The table above describes the smoking habits of a group of asthma sufferers. If one of the 1197 people is randomly selected, find the probability of getting a regular or heavy smoker. | back 11 0.201 (162/1197) + (78/1197) |
front 12 Find the probability that 3 randomly selected people all have the same birthday. Ignore leap years. Round to eight decimal places. | back 12 0.00000751 (1) x (1/365) x (1/365) |
front 13 A sample of 100 wood and 100 graphite tennis rackets are taken from the warehouse. If 6 wood and 14 graphite are defective and one racket is randomly selected from the sample, find the probability that the racket is wood or defective. | back 13 0.57 (100/200) + (20/200) – (6/200) |
front 14 100 employees of a company are asked how they get to work and whether they work full time or part time. The figure above shows the results. If one of the 100 employees is randomly selected, find the probability of getting someone who carpools or someone who works full time. 1. Public transportation: 7 full time, 10 part time 2. Bicycle: 4 full time, 3 part time 3. Drive alone: 30 full time, 31 part time 4. Carpool: 6 full time, 9 part time | back 14 0.56 (15/100) + (47/100) – (6/100) |
front 15 The probability that Luis will pass his statistics test is 0.90. Find the probability that he will fail his statistics test. | back 15 0.10 1 – 0.90 |
front 16 Find the z-score corresponding to the given value and use the z-score to determine whether the value is unusual. Consider a score to be unusual if its z-score is less than -2.00 or greater than 2.00. Round the z-score to the nearest tenth if necessary. A weight of 110 pounds among a population having a mean weight of 164 pounds and a standard deviation of 25.6 pounds. | back 16 –2.1; unusual (110 – 164) ÷ 25.6 = -2.11 |
front 17 Find the z-score corresponding to the given value and use the z-score to determine whether the value is unusual. Consider a score to be unusual if its z-score is less than -2.00 or greater than 2.00. Round the z-score to the nearest tenth if necessary. A | back 17 –1.9; not unusual (50 – 69) ÷ 10 = -1.9 |
front 18 The histogram above represents the number of television sets per household for a sample of U.S. households. What is the maximum number of households having the same number of television sets? | back 18 50 |
front 19 When finding percentiles, if the locator L is not a whole number, one procedure is to interpolate so that a locator of 23.75, for example, leads to a value that is 3/4 of the way between the 23rd and 24th scores. Use this method of interpolation to find P_{75} for the set of test scores above. | back 19 89 |
front 20 A computer company employs 100 software engineers and 100 hardware engineers. The personnel manager randomly selects 20 of the software engineers and 20 of the hardware engineers and questions them about career opportunities within the company. Does this sampling plan result in a random sample? Simple random sample? Explain. | back 20 Yes; no. The sample is random because all employees have the same chance of being selected. It is not a simple random sample because some samples are not possible, such as a sample consisting of 30 software engineers and 10 hardware engineers. |
front 21 A researcher obtains an alphabetical list of the 2560 students at a college. She uses a random number generator to obtain 50 numbers between 1 and 2560. She chooses the 50 students corresponding to those numbers. Does this sampling plan result in a random sample? Simple random sample? Explain. | back 21 Yes; yes. The sample is random because all students have the same chance of being selected. It is a simple random sample because all samples of 50 students have the same chance of being selected. |
front 22 An education expert is researching teaching methods and wishes to interview teachers from a particular school district. She randomly selects ten schools from the district and interviews all of the teachers at the selected schools. Does this sampling plan result in a random sample? Simple random sample? Explain. | back 22 Yes; no. The sample is random because all teachers have the same chance of being selected. It is not a simple random sample because some samples are not possible, such as a sample that includes teachers from schools that were not selected. |
front 23 The frequency table above shows the number of days off in a given year for 30 police detectives. Construct a histogram. Use the class midpoints for the horizontal scale. Does the result appear to be a normal distribution? Why or why not? | back 23 The distribution does not appear to be normal. It is not bell-shaped and it is not symmetric. |
front 24 Construct a frequency distribution and the corresponding histogram in which the following conditions are satisfied: – The frequency for the second class is twice the frequency of the first class. – In the histogram, the area of the bar corresponding to the second class is four times the area of the bar corresponding to the first class. | back 24 The class width of the second class should be twice the class width of the first class. |
front 25 Sturges' guideline suggests that when constructing a frequency distribution, the ideal number of classes can be approximated by 1 + (log n)/(log 2), where n is the number of data values. Use this guideline to find the ideal number of classes when the number of data values is 33. | back 25 6 1 + (log 33)/(log 2) = 6.044394119 |
front 26 Human body temperatures have a mean of 98.20°F and a standard deviation of 0.62°. Sally's temperature can be described by z =1.4. What is her temperature? Round your answer to the nearest hundredth. | back 26 99.07°F x = z × σ + µ x = 1.4 × 0.62 + 98.2 x = 99.068 |
front 27 A nurse measured the blood pressure of each person who visited her clinic. Following is a relative-frequency histogram for the systolic blood pressure readings for those people aged between 25 and 40. The blood pressure readings were given to the nearest whole number. What class width was used to construct the relative frequency distribution? | back 27 10 (110 – 100) |
front 28 The frequency distribution above summarizes the home sale prices in the city of Summerhill for the month of June. Determine the width of each class. | back 28 31 (111.0 – 80.0) |
front 29 The following frequency distribution analyzes the scores on a math test. Find the class midpoint of scores interval 95-99. | back 29 97.0 (99 – 95) ÷ 2 = 2 95 + 2 = 97 |
front 30 The table contains data from a study of daily study time for 40 students from Statistics 101. Construct an ogive from the data. | back 30 |
front 31 The frequency distribution for the weekly incomes of students with part-time jobs is given above. Construct the corresponding relative frequency distribution. Round relative frequencies to the nearest hundredth of a percent if necessary. | back 31 |
front 32 Use the given data to construct a frequency distribution. Lori asked 24 students how many hours they had spent doing homework during the previous week. The results are shown above. Construct a frequency distribution. Use 4 classes, a class width of 2 hours, and a lower limit of 8. | back 32 |
front 33 Identify the type of observational study (cross-sectional, retrospective, prospective). A town obtains current employment data by polling 10,000 of its citizens this month. | back 33 Cross-sectional |
front 34 Identify the type of observational study (cross-sectional, retrospective, prospective). Researchers collect data by interviewing athletes who have won olympic gold medals from 1992 to 2008. | back 34 Retrospective |
front 35 Is Event B dependent or independent of Event A? A: A green ball is drawn from a box with five balls and placed next to the box. B: A red ball is drawn next and placed next to the green one. | back 35 Dependent |
front 36 Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day. | back 36 Convenience |
front 37 Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag. | back 37 Random |
front 38 Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. 49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively. | back 38 Stratified |
front 39 Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. A market researcher selects 500 people from each of 10 cities. | back 39 Stratified |
front 40 Find the range for the given sample data. The manager of an electrical supply store measured the diameters of the rolls of wire in the inventory. The diameters of the rolls (in meters) are listed below. 0.177 0.115 0.542 0.413 0.618 0.315 | back 40 0.503 m (0.618 – 0.115) |
front 41 Find the range for the given sample data. The prices (in dollars) of 12 electric smoothtop ranges are listed below. 835 950 625 535 1435 1050 650 735 760 1250 525 1035 | back 41 $910
(1435 – 525) |
front 42 From the information provided, create the sample space of possible outcomes. Both Fred and Ed have a bag of candy containing a lemon drop, a cherry drop, and a lollipop. Each takes out apiece and eats it. What are the possible pairs of candies eaten? | back 42 LD-LD CD-LD LP-LP LD-CD CD-CD LD-LP LP-CD CD-LP LP-LD |
front 43 Express the indicated degree of likelihood as a probability value. "It will definitely turn dark tonight." | back 43 1 |
front 44 Use the data to create a stemplot. The normal monthly precipitation (in inches) for August is listed for 39 different U.S. cities. Construct an expanded stemplot with about 9 rows. 3.5 1.6 2.4 3.7 4.1 3.9 1.0 3.6 1.7 0.4 3.2 4.2 4.1 4.2 3.4 3.7 2.2 1.5 4.2 3.4 2.7 4.0 2.0 0.8 3.6 3.7 0.4 3.7 2.0 3.6 3.8 1.2 4.0 3.1 0.5 3.9 0.1 3.5 3.4 | back 44 |
front 45 Use the data to create a stemplot. The attendance counts for this season's basketball games are listed below. 227 239 215 219 221 233 229 233 235 228 245 231 | back 45 |
front 46 Solve the problem. Round results to the nearest hundredth. The mean height of a basketball team is 6 feet with a standard deviation of 0.2 feet. The team's center is 6.7 feet tall. Find the center's z score. Is his score unusual? | back 46 3.5, yes z = (x – µ) ÷ σ = (6.7 – 6) ÷ 0.2 = 3.5 3.5 > 2.00 (unusual) |
front 47 Determine whether the given value is from a discrete or continuous data set. The total number of phone calls a sales representative makes in a month is 425. | back 47 Discrete |
front 48 Determine whether the given value is from a discrete or continuous data set. The number of limbs on a 2-year-old oak tree is 21. | back 48 Discrete |
front 49 Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Nationalities of survey respondents. | back 49 Nominal |
front 50 Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Student's grades, A, B, or C, on a test. | back 50 Ordinal |
front 51 Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Salaries of college professors. | back 51 Ratio |
front 52 Find the variance for the given data. Round your answer to one more decimal place than the original data. –12 6 –3 6 12 | back 52 88.2 s = 9.391485505 variance = s^{2} = 88.19999999 |
front 53 Find the percentile for the data value. Data set: 122 134 126 120 128 130 120 118 125 122 126 136 118 122 124 119; data value: 128 | back 53 75 |
front 54 Find the midrange for the given sample data. 3 6 9 0 4 1 11 5 9 14 3 8 2 15 0 9 | back 54 7.5 (15 – 0) ÷ 2 = 7.5 |
front 55 The pie chart above gives the number of students in the residence halls at the state university. Write the ratio of the number of residents at Adams to the number of students at Evans. | back 55 23:30 Adams: 115 Evans: 150 115:150 |
front 56 The pie chart shows the percent of the total population of 73,700 of Springfield living in the given types of housing. Round your result to the nearest whole number. Find the number of people who live in duplexes. | back 56 3685 people Duplex: 5% 73,700 × 5% = 3,685 |
front 57 A student earned grades of A, C, A, A, and B. Those courses had these corresponding numbers of credit hours: 1, 6, 3, 1, 3. The grading system assigns quality points to letter grades as follows: A = 4, B = 3, C = 2, D = 1, and F = 0. Compute the grade point average (GPA) and round the result to two decimal places. | back 57 2.93 L1: 4, 2, 4, 4, 3 L2: 1, 6, 3, 1, 3 1-Var Stats: x̄ = 2.928571429 |
front 58 Construct one table that includes relative frequencies based on the two frequency distributions below. Do those weights appear to be about the same or are they substantially different.? Round to the nearest tenth of a percent if necessary. | back 58 The weights are different, but they do not appear to be substantially different. |
front 59 At the National Criminologists Association's annual convention, participants filled out a questionnaire asking what they thought was the most important cause for criminal behavior. The tally is shown above. Construct a Pareto chart to display these findings. | back 59 |
front 60 The data shows the roundtrip mileage that 43 randomly selected professors and students drive to school each day. Compare the results by constructing two frequency polygons on the same axes, and determine whether there appears to be any significant difference between the two groups. | back 60 There does not appear to be a significant difference. |
front 61 The coefficient of variation, expressed as a percent, is used to describe the standard deviation relative to the mean. It allows us to compare variability of data sets with different measurement units and is calculated as follows: coefficient of variation = 100 (s/x̄) Find the coefficient of variation for the following sample of weights (in pounds): 130 127 186 105 197 153 172 150 116 125 | back 61 21.1% |
front 62 Find the mode(s) for the given sample data. –20 –43 –46 –43 –49 –43 –49 | back 62 –43 |
front 63 Find the coefficient of variation for each of the two sets of data, then compare the variation. Round results to one decimal place. Compare the variation in heights to the variation in weights of thirteen-year old girls. The heights (in inches) and weights (in pounds) of nine randomly selected thirteen-year old girls are listed below. Heights (inches): 59.1 61.3 62.1 64.7 60.1 58.3 64.6 63.7 66.1 Weights (pounds): 87 94 91 119 96 90 123 98 139 | back 63 Heights: 4.4% Weights: 17.5% There is substantially more variation in the weights than in the heights of the girls. |
front 64 If you drew one card from a standard deck, would it be "unusual" to draw an eight of clubs? | back 64 Yes 1/52 = 0.019 < 0.05 |
front 65 Assume that a study of 300 randomly selected school bus routes showed that 278 arrived on time. Is it "unusual" for a school bus to arrive late? | back 65 No 278/300 = 0.927 < 0.95 (complement of 0.05) |
front 66 Find the original data from the stemplot. | back 66 61, 67, 71, 71, 73, 75, 81, 83, 83, 87, 89, 93, 95 |
front 67 Construct a pie chart representing the given data set. The following figures give the distribution of land (in acres) for a county containing 70,000 acres. Forest Farm Urban 10,500 7000 52,50 | back 67 |
front 68 Find the standard deviation for the given sample data. Round your answer to one more decimal place than is present in the original data. 20.0 21.5 27.4 47.3 13.1 11.1 | back 68 13.11 |
front 69 Use the range rule of thumb to estimate the standard deviation. Round results to the nearest tenth. The maximum value of a distribution is 23.6 and the minimum value is 7.4. | back 69 4.1 |
front 70 A polling firm, hired to estimate the likelihood of the passage of an up-coming referendum, obtained the set of survey responses to make its estimate. The encoding system for the data is: 1 = FOR,2 = AGAINST. If the referendum were held today, estimate the probability that it would pass. 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1 | back 70 0.6 |
front 71 The local Tupperware dealers earned these commissions last month: $1077.28 $2661.13 $4642.11 $4264.15 $1019.55 $3444.20 $2525.92 $3740.26 $3533.07 $1633.84 What was the mean commission earned? Round your answer to the nearest cent. | back 71 $2854.15 |
front 72 Identify the sample and population. Also, determine whether the sample is likely to be representative of the population. 100,000 randomly selected adults were asked whether they drink at least 48 oz of water each day and only 45% said yes. | back 72 Sample: the 100,000 selected adults; population: all adults; representative |
front 73 Find the mean of the data summarized in the given frequency distribution. A company had 80 employees whose salaries are summarized in the frequency distribution below. Find the mean salary. | back 73 $17,125.00 |
front 74 What is the probability of an impossible event? | back 74 0 |
front 75 Determine whether the events are disjoint. Draw one ball colored red from a bag. Draw one ball colored blue from the same bag. | back 75 Yes |
front 76 Determine whether the events are disjoint. Go to a formal dinner affair. Wear blue jeans. | back 76 Yes |
front 77 Determine whether the given value is a statistic or a parameter. After taking the first exam, 15 of the students dropped the class. | back 77 Parameter |
front 78 Construct the dotplot for the given data. The following data represent the number of cars passing through a toll booth during a certain time period over a number of days. 18 19 17 17 24 18 21 18 19 15 22 19 23 17 21 | back 78 |
front 79 Construct a boxplot for the given data. Include values of the 5-number summary in all boxplots. The test scores of 32 students are listed below. Construct a boxplot for the data set. 32 37 41 44 46 48 53 55 57 57 59 63 65 66 68 69 70 71 74 74 75 77 78 79 81 82 83 86 89 92 95 99 | back 79 |