Final Exam Review
A sample of 10 packs of a brand of chewing gum was taken. Each pack was weighed and their weights, in grams, are shown. 43.0, 43.7, 49.6, 46.9, 47.6, 45.4, 51.2, 48.0, 40.5, 49.1 What is the z-score for the pack of gum weighing 43 grams?
-1.05
A basketball player averages 22.5 points scored per game with a standard deviation of 6.2 points. In one game, the number of points the athlete scored was 1.2 standard deviations below the mean. Which of the following is the z-score for the number of points scored?
-1.2
The lengths of the red drum species of fish are approximately Normally distributed, with a mean length of 24 inches and a standard deviation of 1.4 inches. What proportion of red drum fish are less than 23 inches in length?
0.2389
The lengths of the red drum species of fish have an approximately Normal distribution, with a mean length of 24 inches and a standard deviation of 1.4 inches. What proportion of red drum fish are between 22 and 23.5 inches in length?
0.2830
The diameters of cherry tomatoes produced by a large farm have an approximately Normal distribution, with a mean diameter of 22 mm and a standard deviation of 2.5 mm. What proportion of such tomatoes have a diameter between 20 and 26 mm?
0.7333
The president of the student council wants to survey the student population about parking. She decides to take a random sample of 100 of the 1,020 students at the school. Which of the following correctly labels the population?
0001-1020
A greenhouse owner wants to test the effectiveness of a new fertilizer on African violets. She has 60 violet seedlings that were grown for 8 weeks. She wants to test the new fertilizer on 10 of the plants, and decides to use a random number table to select a simple random sample. Which of the following correctly labels the population of violets?
01-60
In a certain breed of cattle, the length of gestation has a mean of 284 days and a standard deviation is 5.5 days. What is the z-score for a gestation period that lasts 290 days?
1.09
The times for running a 5K for a local charity event are Normally distributed. Which standardized time represents the 87th percentile?
1.13
In a statistics class, students were asked how many siblings they have. Their responses are shown. 2, 3, 1, 3, 5, 3, 3, 3, 6, 3, 5, 0, 3 What is the z-score for the student with five siblings?
1.19
The graph shows the distribution of the amount of time (in minutes) people spend watching TV shows on a popular streaming service. The distribution is approximately Normal, with a mean of 71 minutes and a standard deviation of 15 minutes. What percentage of people spend between 41 and 56 minutes watching TV shows on this streaming service?
13.5%
The graph shows the distribution of the amount of chicken (in ounces) that adults eat in one sitting. The distribution is approximately Normal, with a mean of 8 ounces and a standard deviation of 1.2 ounces. What percentage of adults eat between 9.2 and 11.6 ounces of chicken in one sitting?
15.85%
The salt content in snack bags of pretzels is Normally distributed, with a mean of 180 mg and a standard deviation of 15 mg. Eighty four percent of bags have a salt content higher than which value?
165.2 mg
The times for running a 5K for a local charity event are Normally distributed, with a mean time of 28 minutes and standard deviation of 5.4 minutes. Which time represents the fastest 4% of runners?
18.55 minutes
The graph shows the distribution of the lengths (in seconds) of videos on a popular video-streaming site. The distribution is approximately Normal, with a mean of 264 seconds and a standard deviation of 75 seconds. Sixteen percent of videos are shorter than what length?
189 seconds
The salt content in snack bags of pretzels is Normally distributed, with a mean of 180 mg and a standard deviation of 15 mg. Eighty four percent of bags have a salt content lower than which value?
194.9 mg
The graph shows the distribution of the amount of chicken (in ounces) that adults eat in one sitting. The distribution is approximately Normal, with a mean of 8 ounces and a standard deviation of 1.2 ounces. What percentage of adults eat more than 10.4 ounces of chicken in one sitting?
2.5%
The graph shows the distribution of the number of text messages young adults send per day. The distribution is approximately Normal, with a mean of 128 messages and a standard deviation of 30 messages. According to the graph, 99.85% of young adults send fewer than what number of text messages?
218
A machine at a food-distribution factory fills boxes of rice. The distribution of the weights of filled boxes of rice has an approximately Normal distribution, with a mean of 28.2 ounces and a standard deviation of 0.4 ounces. What percentage of filled boxes of rice have a weight less than 27.9 ounces?
22.7%
In a certain breed of cattle, the length of gestation has a mean of 284 days and a standard deviation is 5.5 days. What length of gestation, rounded to the nearest whole number, represents the 18th percentile?
279 days
A runner's distribution of times for running 1,000 meters has a mean of 4.5 minutes with a standard deviation of 0.75 minutes. One of the runner's times has a z-score of -1.76. What is the runner's time?
3.18 minutes
In a standard Normal distribution, what percentage of observations lie between z = 0.37 and z = 1.65?
30.62%
Keeping car tires inflated is essential to safe driving. For one type of car tire, the tire pressure in pounds per square inch (psi) is assumed to be approximately Normal, with a mean of 35 psi and a standard deviation of 2 psi. What percentage of tires are inflated to a pressure above 36 psi?
30.85%
The graph shows the distribution of the number of text messages young adults send per day. The distribution is approximately Normal, with a mean of 128 messages and a standard deviation of 30 messages. What percentage of young adults send between 128 and 158 text messages per day?
34%
Weights of four-year-olds are Normally distributed, with a mean of 40 pounds and a standard deviation of 1.3 pounds. At his four-year checkup, Marlon's weight is measured to be greater than 30% of boys his age. How much does Marlon weigh?
39.3 pounds
The president of the student council wants to survey the student population about parking. She decides to use a random number table to take a random sample of 100 of the 1,020 students at the school. What is the smallest number of digits that should be used to label the population?
4
At the Fisher farm, the weights of zucchini squash are Normally distributed, with a mean of 5 ounces and a standard deviation of 0.7 ounces. Which weight represents the 8th percentile?
4.01 ounces
In a standard Normal distribution, what percentage of observations lie above z = 1.65?
4.95%
Heights of four-year-olds are Normally distributed, with a mean of 40 inches and a standard deviation of 3 inches. At his four-year checkup, Marlon's height is measured as taller than 70% of boys his age. How tall is Marlon?
41.6 inches
Heights of four-year olds are Normally distributed, with a mean of 40 inches and a standard deviation of 3 inches. At her four-year checkup, Hannah's height measures in the 99th percentile. How tall is Hannah?
47.0 inches
Scores on a national math test are Normally distributed, with a mean score of 490 and a standard deviation of 50. Which test score represents the top 20%, rounded to the nearest whole number?
532
Scores on a national English test are Normally distributed, with a mean score of 510 and a standard deviation of 75. Jaxon's test score is in the 85th percentile. What is his test score, rounded to the nearest whole number?
588
The daily high temperatures in a vacation resort city are approximately Normal, with a mean temperature of 75 degrees Fahrenheit and a standard deviation of 6 degrees. What percentage of days have a high temperature below 77 degrees?
62.93%
A basketball player averages 22.5 points scored per game with a standard deviation of 6.2 points. In one game, the number of points the athlete scored was 1.2 standard deviations below his mean. How many points below average was this value?
7.44
Bags of flour at a local grocery store have a mean weight of 83 ounces with a standard deviation of 2 ounces. The manufacturer of the flour states that 5% or less of the bags are underweight. What is this weight?
79.7 ounces
On a unit test in a statistics class, the teacher determines that the mean test grade was 77.5 with a standard deviation of 5.2. What is the test grade, rounded to the nearest whole number, with a z-score of 2.4?
90
The graph shows the distribution of the length of videos (in seconds) on a popular video-sharing site. The distribution is approximately Normal, with a mean of 264 seconds and a standard deviation of 75 seconds. What percentage of videos have lengths that are between 114 and 414 seconds?
95%
The graph shows the distribution of weights (in pounds) of male duck-billed platypuses. The distribution is approximately Normal, with a mean of 3.75 pounds and a standard deviation of 0.52 pounds. What percent of male duck-billed platypuses have a weight of between 2.71 and 4.79 pounds?
95%
The graph shows the distribution of the length (in seconds) of videos on a popular video-streaming site. The distribution is approximately Normal, with a mean of 264 seconds and a standard deviation of 75 seconds. What percentage of videos on the streaming site are between 114 and 489 seconds?
97.35%
When people are discharged from a hospital, they are surveyed about the quality of their stay. The hospital asks each person to turn in the survey before leaving. Is this a simple random sample?
No, because each person is asked to fill out the survey, so this is not a sample.
Some newer phones provide a screen time summary, which shows the amount of screen time for a user in a given week. A student would like to estimate the mean screen time for all phone users. She asks a random sample of 50 students at her school to share their screen time for the past 24 hours. The mean screen time for the chosen students is 2.73 hours. Which statement is an appropriate interpretation of the results?
Because of undercoverage, 2.73 likely underestimates the mean screen time of all phone users.
Many adults owe money from their college loans for years into their professional careers. A newspaper would like to estimate the proportion of all adults in the city who have debts from college loans. To collect data, a random sample of 300 young adults between the ages of 25 and 35 is asked, "Do you have more than $5,000 in current college debts?" 68% of those sampled reported that they do have more than $5,000 in college-related debts. How might this sample be biased in obtaining an estimate of all adults in the city who have college debts?
Because only young adults were sampled, undercoverage bias may cause the newspaper to overestimate the proportion of all adults who have college debts.
A random sample of adults in a large US city responded to a series of questions about their use of public transportation. The results of the survey showed that 520 of the 838 adults in the sample (62%) have used public transportation in the past week. How might the results of the survey be biased in obtaining an estimate of all US residents who use public transportation?
Because the sample includes only residents in one US city, the survey may overestimate the proportion of US adults who use public transportation.
To increase attendance for a flower show, flower shops in the area offered discount coupons to their customers. Show attendance was higher this year, which the organizers attributed to the many discount coupons attendees used. However, the organizers are warned that weather could be a confounding variable in interpreting the rise in attendance. Which statement could explain the effect of confounding?
Because the weather was generally better this year compared to last year, the attendance may have increased.
To estimate the mean number of text messages sent by cell-phone users, a researcher chooses a location on a college campus in the city and surveys the first 50 people who walk past. These subjects are asked how many text messages they have sent in the past 24 hours. Is it likely that bias will be present in the sample?
Because this is a convenience sample of college students, it is likely that bias is present and that the results will overestimate the mean number of text messages sent.
An auto-parts store offers a fuel additive that claims to increase a vehicle's gas mileage. The additive is poured into a vehicle's gasoline tank after the tank is filled. To measure the claim, the store offers a free bottle of the additive to customers who drive SUV's, who then provide information about their gas mileage on the store website. A customer argues that the type of vehicle could be a confounding variable in this study. Which statement best describes the effect of the confounding variable?
Because vehicles of different sizes may respond differently to the additive, it may be difficult to conclude whether the additive improves gas mileage for all vehicles.
Real estate agents in a county with a large, urban residential area noticed that families with larger incomes tend to live in homes that sell for higher prices. What are the explanatory variable and response variable for this relationship?
Explanatory variable: family incomeResponse variable: price of the home
At age six, Kylie is 50 inches tall. Her height has a z-score of 1.8. At age four, Hannah is 48 inches tall. Her height has a z-score of 2.1. Relative to girls their ages, who is taller?
Hannah is taller because her z-score is higher than Kylie's z-score.
A hotel rewards club wants to randomly select 100 of its 5,000 members to participate in a survey. The club wants to determine if people's opinions differ based on age. There are 2,200 members between the ages of 25 and 50, and there are 2,800 who are age 51 or older. The club decides to randomly select 44 members between the ages of 25 and 50, and 56 members ages 51 and older. Is the sample of 100 members a simple random sample?
No, because each sample of 100 does not have the same chance of being selected.
The president of the student council wants to survey the student population. She decides to take a random sample of 100 students. She puts every student's name on a rectangular slip of paper, each with the same length and width. Then she places the slips of paper into a hat and, without looking, selects 100 slips of paper. Is this a simple random sample?
No, because she did not mix the pieces of paper in the hat before selecting the sample.
A pharmaceutical company develops a new generation of blood pressure medication that may also help with cholesterol. The research and development department advertises in the local papers and online for volunteers who already take blood pressure medication to participate in a study for the new medication. Two hundred people volunteer, and their current blood pressure along with their cholesterol levels are measured. The first 100 volunteers are assigned to the new generation of blood pressure medication, and the next 100 are assigned to the original medication. At the end of the study, the subjects' blood pressures and cholesterol levels are measured. The group with the new medication is found to have significantly lower overall blood pressure than the original medication group. It was also determined that the new medication did not significantly lower cholesterol levels. Which of the following is a valid conclusion?
Inferences cannot be made about all blood pressure patients, and the conclusion cannot be made that the new medication lowers blood pressure more effectively than the original medication for patients taking blood pressure medication.
A botanist wants to determine if a fertilizer is effective in the growth of plants. He selects the first 100 plants of the same type of seedling from a greenhouse and assigns the first 50 to the group that uses the fertilizer and remaining seedlings to the group that does not use fertilizer. He makes sure the plants all have the same amount of water, soil, and light for two months. At the end of two months, he measures the heights of the plants and finds that the ones receiving the fertilizer are significantly taller. Which of the following is a valid conclusion?
Inferences cannot be made for these types of plants, and the conclusion cannot be drawn that the fertilizer will help these types of plants grow taller.
A researcher considers two methods for collecting data to determine if store-brand laundry detergents work as well as name-brand detergents. Method 1: The researcher surveys shoppers as they enter a grocery store. The shoppers are asked which type of detergent they use and then rate the cleanliness of their laundry on a scale from 1 to 10 (with 10 being the cleanest). The ratings of the name-brand detergents are compared to the ratings of the store-brand detergent. Method 2: The researcher creates 10 loads of soiled fabrics and washes 5 of the loads with name-brand detergent and the other 5 with store-brand detergent. Volunteers are asked to assess the cleanliness of the fabrics using a scale from 1 to 10 (with 10 being the cleanest), and the ratings of the name-brand detergents are compared to the ratings of the store-brand detergent. Which method describes an observational study?
Method 1 is an observational study because no attempt is made to influence results.
A clothing company is considering a new insulation for winter coats. To collect customer satisfaction data on the new insulation, the company is considering two methods. Method 1: The company offers the first 50 employees who volunteer to try out a coat with new insulation if they will report their satisfaction level after one month. At the end of the month, the 50 volunteers describe their satisfaction with the coat's performance. Method 2: The company takes 50 volunteers and randomly assigns 25 of them to coats with the new insulation and the other 25 to coats with the current insulation. All volunteers wear the coats for a month and then describe their satisfaction with the coats' performance. Which method describes an experiment?
Method 2 is an experiment because volunteers are assigned one of the two insulation types.
Two methods are proposed to measure the effectiveness of a brand of sunscreen. Method A: Survey adults visiting a beach on a busy weekend. Ask each adult which brand of sunscreen they are using, and assess their arms for sun exposure. Method B: Volunteers are randomly assigned to one of two brands of sunscreen. Each volunteer is asked to report back at the end of the day, and their arms are assessed for sun exposure. Which statement is a correct interpretation of these methods?
Method B is an experiment because it randomly assigns volunteers a sunscreen, while method A is an observational study.
Race organizers want to survey the participating runners on the difficulty of the running course. Which of the following most effectively uses cluster sampling?
Place the runners into groups based on the seconds part of their finishing time (0:00-0:05, 0:06-0:10, etc.). Randomly select 2 of these groups, and survey every runner within the chosen groups.
A paper company wants to survey its employees about a new policy on sales commissions. Which of the following would result in a stratified random sample?
Randomly select 2 people from each department (sales, customer service, accounting, etc.)
A teacher has 36 students who were randomly assigned to 6 rows of 6 desks. She wants to survey the students about the homework policy. Which of the following uses cluster sampling?
Roll a fair number cube. Use the number rolled to pick a row of students. Survey every student in that row.
A teacher is interested in students' opinions about an upcoming school dance. Which of the following techniques uses systematic random sampling?
Survey the 10th student arriving at school (with the number 10 being randomly chosen), then survey every 12th student after that.
Researchers would like to assess the overall health of white pine trees in a state park. Which of the following methods for choosing the trees to assess would be considered a convenience sample?
The 100 trees closest to a ranger station are assessed for damage.
A popular restaurant advertises that it delivers its orders within 30 minutes. Suppose the average delivery time for one store is 27 minutes with a standard deviation of three minutes. One particular order delivery has a z-score of -2.15. Which of the following statements is not a correct interpretation?
The delivery time was slower than the average delivery time by 2.15 standard deviations.
The graph shows the distribution of time (in hours) that teenagers spend playing video games per week. Which statement describes the distribution?
The distribution is approximately Normal, with a mean of 14 hours and a standard deviation of 4 hours.
The graph shows the distribution of the amount of chicken (in ounces) that adults eat in one sitting. Which statement describes the distribution?
The distribution is approximately Normal, with a mean of 8 ounces and a standard deviation of 1.2 ounces.
How far do US workers travel to get to their jobs? To estimate the average distance workers travel, a website includes a survey where adults can share their daily commute distance. What are the population and sample in this setting?
The population is all US workers. The sample is adults who respond to the survey.
A tourist guide for a state provides information on summer vacation towns. Some of the towns and related information are given in the table. Which of the variables is a discrete quantitative variable?
number of hotels
Many large cities have considered or passed proposals that ban the use of plastic grocery bags in stores. A concerned student would like to measure if residents of her hometown would consider a similar ban on plastic bags. Standing in a busy shopping area, the student approaches adults and asks, "Items made of plastics are a dangerous, growing source of pollution to our world's oceans and threaten many animal species. Given this, would you support a ban on plastic shopping bags in our city stores?" How might the results of this survey be biased in estimating the proportion of all town residents who would support a ban on plastic bags?
The student may overestimate support for a plastic bag ban because the wording of the question may influence adults to support a ban.
A teacher gave a unit test to both of her statistics classes. The mean test grade for Class A was 77 points, with a standard deviation of 5 points, whereas the mean test grade for Class B was 80, with a standard deviation of 7 points. Kyle, in Class A, received an 82 on the test, and Caleb, in Class B, received an 87. Whose performance on the unit test was better relative to their class?
They both performed the same because their z-scores have the same value.
What proportion of city residents uses public transportation at least once a week? City planners would like to estimate this proportion and collect information from workers entering a large office building in the center of the city. Which of the following best describes the potential results of this survey?
This is a convenience sample and is likely to overestimate the proportion of residents who take public transportation.
A school cafeteria wants to survey a random sample of 50 students about the quality of food. During one lunch period, every 5th student who walks through the cafeteria door is surveyed until 50 students are selected. Which of the following statements is true about this sample?
This is neither a random sample nor a simple random sample.
Some government leaders propose allowing oil companies to drill in currently protected lands that may be rich in oil reserves. Environmental researchers argue that drilling in such lands would be harmful to the surrounding ecosystem. To measure support for drilling in such lands, an oil company representative uses random-digit telephone dialing to contact adults in the region and measure opinion for increased drilling. One question in the survey asks, "Given that an increase in drilling could result in increased tax revenue and additional jobs to the region, would you support a proposal to allow drilling in lands currently protected from drilling?" What type of bias could be most likely affecting the survey results?
This is question wording bias because the information given at the start of the question may lead those surveyed towards a desired response.
A city government is considering raising the local income tax to pay for improvements to government facilities. A private citizen opposes the plan and stands on a busy street to survey residents with the question, "Do you agree that wasteful spending is a serious problem in our local government?" The results of the survey will most likely suffer from which type of bias?
This is question wording bias because the question leads those surveyed toward a desired response.
A restaurant chain would like to measure the proportion of customers who are generally satisfied with the service provided by its staff. At the end of the meal, as the check is delivered to the table, the server asks those at the table to rate their satisfaction with the service provided as "Very Satisfied," "Satisfied," or "Not Satisfied." During a one-week period, 147 customers were surveyed and 135 (93%) reported they were either Satisfied or Very Satisfied. What type of bias may be present in the survey results?
This is response bias because customers may not respond truthfully to the server.
An economist would like to estimate the proportion of young adults who have college debt. An online survey invites young adults to share information about their level of college debt. Which of the following describes the survey design and potential bias?
This is voluntary response and is likely to overestimate the proportion of young adults with college debt.
A local baseball team is struggling this season, and many fans of the team believe it may be time to replace the head coach. To estimate support for firing the current head coach, a television news station provides a link on its website where fans of the team can respond to the question: "Do you feel the current head coach should be fired?" After 2,367 votes on the website, 79% of those who responded felt the coach should be fired. Which of these describes the type of bias in this survey and a likely direction of the bias in estimating overall support for firing the coach?
This is voluntary response bias. The result overestimates true support for firing the coach.
Several members of a running club would like to survey the rest of the members to determine which 5K race the club should enter. They decide to sample 10 of the 78 members and have them fill out a survey about their race preference. Which of the following would be a simple random sample?
Write each member's name on an equal-sized slip of paper. Place the slips of paper in a bag and shake. Draw 10 slips of paper and survey the members selected.
A consumer agency wants to determine which of two laundry detergents, A or B, cleans better. Fifty pieces of fabric are subjected to the same kinds of stains (grass, mud, coffee). Then 25 pieces are randomly assigned to be cleaned with detergent A, and the remaining 25 pieces are cleaned with detergent B. After being laundered, the pieces of fabric are rated on a scale from 1-10, with 1 being the least clean to 10 being the most clean. The difference in mean ratings (A - B) was determined to be -2.3. Assuming there is no difference in the two detergents, 200 simulated differences in sample means are displayed in the dotplot. Using the dotplot and the difference in mean ratings from the samples, is there convincing evidence that the one detergent is better than the other?
Yes, because a difference in mean rating of -2.3 or less occurred only 5 out of 200 times, meaning the difference is statistically significant, and there is convincing evidence that B is more effective than A.
Manufacturers of tires report that tires should be able to last an average of 50,000 miles. A new tire company produces a different type of tread and tests 100 randomly selected tires. This sample of 100 tires lasted an average of 52,000 miles. Assuming the new type of tread does not improve the mileage of the tire, 200 sample means were simulated and displayed on the dotplot. Using the dotplot and the sample mean mileage, is there convincing evidence that the new type of tread improves the mileage?
Yes, because a mean mileage of 52,000 or more occurred only 7 out of 200 times, the mean mileage is statistically significant. There is convincing evidence the new type of tire tread improves mileage of the tire.
A teacher assigns 10 questions for homework and wants to randomly pick 3 questions to be graded. He writes the numbers 1-10 on equally sized slips of paper and places them in a bag. He shakes the bag and selects 3 slips of paper. Is the sample of 3 questions a simple random sample?
Yes, because the paper slips were equally sized and the bag was shaken.
A manufacturer of bottled tea runs a promotion, where consumers can win a free bottle of tea if the cap of the bottle says "Winner." The manufacturer claims that 1 in 5 bottles is a winner. Jack really likes the tea and has noticed that the last 10 bottles he has bought has not had a winner. Suspecting the manufacturer's claim is false, Jack decides to select 10 bottles of tea from 10 randomly selected stores. He is surprised again when none of the 10 bottles is a winner. Assuming the manufacturer's claim is true, Jack simulates 100 values of selecting winners in 10 bottles. The dotplot displays these simulated proportions. Using the dotplot and the proportion of winners in Jack's sample, is there convincing evidence that the manufacturer's claim is wrong?
Yes; because a proportion of 0 occurred 3 out of 100 times, the sample proportion of winners is statistically significant and there is convincing evidence that the manufacturer's claim is false.
During a particularly dry growing season in a southern state, farmers noticed that there is a delicate balance between the number of seeds that are planted per square foot and the yield of the crop in pounds per square foot. The yields were the smallest when the number of seeds per square foot was either very small or very large. The data in the table show various numbers of seeds planted per square foot and yields (in pounds per square foot) for a sample of fields. Which scatterplot represents the seed and yield data?
a
To attract business, a clothing store mails discount coupons to local residents. To estimate the proportion of the store's shoppers who are using the coupons, the store manager selects a random sample of 100 customers who visit the store on a weekend. The manager finds that 38 of them are using the coupons mailed to their homes. Which of the following describes the population in this setting?
all shoppers in the store on the weekend
An automotive website would like to estimate the percentage of drivers who own their cars, rather than lease their cars. Which of these survey methods would not provide a convenience sample to estimate the percentage who own their cars?
an online survey for sharing data about their cars
Many people enjoy taking cruises for their vacations. Each cruise ship has different options and features. Which of the following is an example of a continuous quantitative variable that might be reported about each cruise ship?
average speed in the ocean
A band director is trying to decide what music to play for the halftime show. To get a sample, the director divides the band into groups based on their grade (freshmen, sophomores, juniors, and seniors). Then she randomly chooses a group and surveys every member of the chosen group. Which sampling method was used?
cluster sampling
Education researchers are interested in the workload expectations of freshmen at a local university. Since all of the freshmen are randomly placed into freshman seminar classes, the researchers randomly select 3 freshman seminar classes and survey all of the students within those classes. Which sampling method was used?
cluster sampling
Which scatterplot demonstrates the strongest relationship between two quantitative variables?
d
A golf course has 18 holes. A guidebook provided to golfers includes useful information about each hole, as shown below. What are the individuals in this data set?
holes
A movie theater offers many movie selections for its customers. The table below shows a summary of five movies currently offered and whether the movie is appropriate for children. What are the individuals in the data set?
movie titles
A family visits a car show to research information on vehicles they might consider purchasing. Brochures for each vehicle provide helpful information for the vehicle. Which of the following is an example of a discrete quantitative variable that might be included in the brochure?
number of seats
An airline uses many different types of airplanes. Information regarding some of the airplanes is given in the table below. Which of the variables is a continuous variable?
seat width
A business is interested in employees' job satisfaction. The regional manager places a name card for every employee into a bowl and randomly selects 10 cards. Which sampling method was used?
simple random sampling
A local vet wants to survey his clients about their satisfaction regarding the care their pet received. He groups all of the clients by the type of pet they have (dog, cat, bird, exotic, or multiple), then randomly selects 5 people from each group. Which sampling method was used?
stratified random sampling
The scatterplot illustrates the relationship between distance and success rate of field-goal attempts for a sample of football kickers. The relationship in the scatterplot is
strong and negative.
A sandwich shop owner wants to survey customers about new menu options. To get the sample, the owner surveys the 4th customer of the day (with 4 being a randomly chosen value), then surveys every 10th customer after that. Which sampling method was used?
systematic random sampling
To attract business, a clothing store mails discount coupons to residents of a town. To estimate the proportion of the store's shoppers who are using the coupons, the store manager selects a random sample of 100 customers who visit the store on a weekend. The manager finds that 38 of them are using the coupons mailed to their homes. Which of the following describes the sample in this setting?
the 100 randomly selected shoppers
Researchers would like to assess the overall health of white pine trees in a state park. Using a computer program, the researchers selected 100 random points in the state park and assessed the trees closest to the selected points. Of the 100 trees selected, 24 showed damage to their lower limbs. Which of the following describes the sample in this setting?
the 100 trees checked for damage
Auto racing is a sport enjoyed by many people. In each race, there may be up to 25 cars on the racetrack. Which of the following is NOT an example of a quantitative variable you might use to describe a car in a race?
the brand of car
An auto-parts store offers a fuel additive that claims to increase a vehicle's gas mileage. The additive is poured into a vehicle's gasoline tank after the tank is filled. To measure the claim, 30 taxi drivers receive a bottle of the additive to use the next time they fill their gas tank. The drivers then compare their gas mileage with the additive to their gas mileage before the additive was used. What is the response variable in this scenario?
the gas mileage after the additive is used
A brand of popcorn instructs users to microwave for 90-120 seconds on high. A student wonders what the ideal microwave time for popcorn might be and designs an experiment to find out. Bags of popcorn are placed in the microwave for different lengths of time: 90 seconds, 100 seconds, 110 seconds, and 120 seconds. Also, 2 types of microwaves with different power capacity will be used: 900 watts and 1,000 watts. At the end of the experiment, the number of unpopped kernels will be counted. Using 3 lengths of time and 2 types of microwaves describes which part of the experiment?
the levels
A visitor guide for a downtown area lists many restaurants. Which of the following is an example of a quantitative variable the guide could report for each restaurant?
the number of seats in the restaurant