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- 1. Multiple Choice
The dotplot displays the total number of miles that the 28 residents of one street in a certain community traveled to work in one five-day workweek. Which of the following is closest to the percentile rank of a resident from this street who traveled 85 miles to work that week?
60
70
75
80
85
- 2. Multiple Choice
A large SRS of people aged 19 to 30 living in the state of Colorado was surveyed to determine which of two MP3 players just developed by a new company was preferred. To which of the following populations can the results of this survey be safely generalized?
Only people aged 19 to 30 living in Colorado who were in this survey.
Only people aged 19 to 30 living in Colorado
All people living in Colorado
Only people 19 to 30 living in the United States
All people living in the United States
- 3. Multiple Choice
Janelle collected data on the amount of time in minutes each person in a large sample of customers spent in a local store. The data also included recording the gender of each customer. These data were used to generate the boxplots. Which of the following statements is true?
The range in the amount of time males in the sample of customers spent in the store is approximately 40 minutes.
The mean amount of time males in the sample of customers spent in the store is approximately 20 minutes.
The third quartile of the amount of time males in the sample of customers spent in the store is approximately 45 minutes
The interquartile range of the amount of time males in the sample of customers spent in the store is approximately 15 minutes
Approximately half of the males in the sample of customers spent at least as much time in the store as any female in the sample of customers.
- 4. Multiple Choice
The probability of obtaining a head when a certain coin is flipped is about 0.65. Which of the following is closest to the probability that heads would be obtained 15 or fewer times when this coin is flipped 25 times?
0.14
0.37
0.39
0.60
0.65
- 5. Multiple Choice
The buyer for an electronics store wants to estimate the proportion of defective wireless game controllers in a shipment of 5,000 controllers from the store's primary supplier. The shipment consists of 200 boxes each containing 25 controllers. The buyer numbers the boxes from 1 to 200 and randomly selects six numbers in that range. She then opens the six boxes with the corresponding numbers, examines all 25 controllers in each of these boxes, and determines the proportion of the 150 controllers that are defective. What type of sample is this?
Biased random sample
Convenience sample
Simple random sample
Stratified random sample
Cluster random sample
- 6. Multiple Choice
Which of the following scatterplots could represent a data set with a correlation coefficient of r = -1?
- 7. Multiple Choice
An environmental scientist wants to test the null hypothesis that an antipollution device for cars is not effective. Under which of the following conditions would a Type I error be committed?
The scientist concludes that the antipollution device is effective when it actually is not.
The scientist concludes that the antipollution device is not effective when actually is.
The scientist concludes that the antipollution device is effective when it actually is.
The scientist concludes that the antipollution device is not effective when it actually is not.
A Type I error cannot be committed in this situation.
- 8. Multiple Choice
A data set of test scores is being transformed by applying the following rule to each of the raw scores.
Transformed score = 3.5(raw score) + 6.2
Which of the following is NOT true?
Hint : Use your purple sheet
The mean transformed score equals 3.5(the mean raw score) + 6.2
The median transformed score equals 3.5(the median raw score) + 6.2
The range of the transformed scores equals 3.5(the range of the raw scores) + 6.2
The standard deviation of the transformed scores equals 3.5(the standard deviation of the raw scores)
The IQR of the transformed scores equals 3.5(the IQR of the raw scores)
- 9. Multiple Choice
A random sample of 25 households from the Mountainview School District was surveyed. In this survey, data were collected on the age of the youngest child living in each household. The histogram displays the data collected in the survey. In which of the following intervals is the median of these data collected?
0 to 2
4 to 6
6 to 8
8 to 10
10 to 12
- 10. Multiple Choice
Based on a random sample of 50 students, the 90 percent confidence interval for the mean amount of money students spend on lunch at a certain high school is found to be ($3.45, $4.15). Which of the following statements is true?
90% of the time, the mean amount of money that all students spend on lunch at this high school will be between $3.45 and $4.15.
90% of all students spend between $3.45 and $4.15 on lunch at this high school.
90% of all random samples of 50 students obtained at this high school would result in a sample mean amount of money students spend on lunch between $3.45 and $4.15.
90% of all random samples of 50 students obtained at this high school would result in a 90% confidence interval that contains the true mean amount of money students spend on lunch.
Approximately 45 of the 50 students in the random sample will spend between $3.45 and $4.15 on lunch at this high school.
- 11. Multiple Choice
Ten percent of all Dynamite Mints candies are orange and 45 percent of all Holiday Mints candies are orange. Two independent random samples, each of size 25, are selected - one from Dynamite Mints and the other from Holiday Mints. The total number of orange candies in the two samples is observed. What are the expected total number of orange candies and the standard deviation for the total number of orange candies, respectively, in the two samples?
7 and 2.905
7 and 3.987
13.75 and 2.233
13.75 and 2.905
13.75 and 3.987
- 12. Multiple Choice
In a random sample of 60 shoppers chosen from the shoppers at a large mall, 36 indicated that they had been to a movie in the past month. In an independent random sample of 50 shoppers chosen from the shoppers in the downtown shopping area, 31 indicated that they had been to a movie in the past month. What significance test should be used to determine whether these data provide sufficient evidence to reject the hypothesis that the proportion of shoppers at the mall who had been to a movie in the past month is the same as the proportion of shoppers in the downtown shopping area who had been to a movie in the past month?
One proportion z-test
One sample z-test for a mean
One sample t-test for a mean
Two proportion z-test
Two sample t-test for means
- 13. Multiple Choice
The National Honor Society at Central High School plans to sample a random group of 100 seniors from all high schools in the state to determine the average number of hours per week spent on homework. A 95 percent confidence interval for the mean number of hours spent on homework will then be constructed using the sample data. Before selecting the sample, the National Honor Society decides that it wants to decrease the margin of error. Which of the following is the best way to decrease the margin of error?
Increase the confidence level to 99%
Use the population standard deviation
Use the sample standard deviation
Decrease the sample size
Increase the sample size
- 14. Multiple Choice
Ninety percent of the people who have a particular disease will have a positive result on a given diagnostic test. Ninety percent of the people who do not have the disease will have a negative result on this test. If 5 percent of a certain population has the disease, what percent of the population would test positive for the disease?
4.5%
5%
10%
14%
90%
- 15. Multiple Choice
A marketing company wants to estimate the proportion of consumer in a certain region of the country who would react favorably to a new marketing campaign. Further, the company wants the estimate to have a margin of error of no more than 5 percent with 90 percent confidence. Of the following, which is closest to the minimum number of consumers needed to obtain the estimate with the desired precision?
136
271
385
542
769
- 16. Multiple Choice
Traffic data revealed that 35 percent of automobiles traveling along a portion of an interstate highway were exceeding the legal speed limit. Using highway cameras and license plate registrations, it was also determined that 52 percent of sports cars were also speeding along the same portion of the highway. What is the probability that a randomly selected car along the same portion of the highway was a speeding sports car?
0.870
0.673
0.182
0.170
It cannot be determined from the information given.
- 17. Multiple Choice
In a large school district, 16 of 85 randomly selected high school seniors play a varsity sport. In the same district, 19 of 67 randomly selected high school juniors play a varsity sport. A 95 percent confidence interval for the difference between the proportion of high school seniors in the district who play a varsity sport and high school juniors in the district who play a varsity sport is to be calculated. What is the standard error of the difference?
0.0347
0.0695
0.1362
0.9800
1.6900
- 18. Multiple Choice
A new restaurant is interested in determining the best time-temperature combination for roasting a five-pound cut of lamb. The times to be tested are 45, 60, and 90 minutes at temperatures of 350 and 425 degrees Fahrenheit, with the exception of the 90 minutes-425 degree combination (which would overcook the lamb). From 10 identical cuts of lamb, 2 are randomly selected to roast using each of the time-temperature combinations in the same oven. The quality of the finished product is evaluated for each roast. Which of the following is true?
The explanatory variable is the quality of the finished lamb.
The response variable is the roasting temperature for the lamb.
If the experiment is repeated, identical results will be expected.
There should be a control group (i.e. a group in which no treatment is given).
The two cuts that are being roasted for each time-temperature combination are an example of replication.
- 19. Multiple Choice
A local real estate magazine used the median instead of the mean when it reported the SAT score of the average student who attends Groveland High School. A graphical display of SAT scores of students who attend GHS indicated that the data were strongly skewed to the right. Which of the following explains why, in this situation, the median is a more accurate indicator of the SAT score of the average student than the mean is?
The mean is affected by the skewness, whereas the median is not.
The median is always the preferred statistic.
The mean will be less than the median when the data are strongly skewed to the right.
The mean should be used only when data are strongly skewed to the left.
The median is equal to one-half the sum of the maximum and minimum SAT scores at GHS.
- 20. Multiple Choice
Raoul performed an experiment using 16 windup rubber band single-propeller airplanes. He would up the propeller a different number of times and recorded the amount of time (in seconds) that the airplane flew for each number of rotations that the propeller was wound. Which of the following is a 95 percent confidence interval for the slope of the regression line that relates the number of rotations to the plane's flight time?
0.0462 ± (2.145)(0.01565)
0.924 ± (2.145)(0.6413)
0.0462 ± (2.96)(0.01565)
0.924 ± (2.96)(0.6413)
0.0462 ± (2.131)(0.01565)
- 21. Multiple Choice
A recent study was conducted to investigate the duration of time required to complete a certain manual dexterity task. The reported mean was 10.2 seconds with a standard deviation of 16.0 seconds. Suppose the reported values are the true mean and standard deviation for the population. If a random sample of 144 subjects is selected, what is the approximate probability that the mean of the sample will be more than 11.0 seconds?
0.1151
0.2743
0.7257
0.8849
cannot be calculated
- 22. Multiple Choice
On their birthdays, employees at a large company are permitted to take a 60-minute lunch break instead of the usual 30 minutes. Data were obtained from 10 randomly selected company employees on the amount of time that each actually took for lunch on his or her birthday. The company wishes to investigate whether these data provide convincing evidence that the mean time is greater than 60 minutes. Of the following, which information would NOT be expected to be a part of the process of correctly conducting a hypothesis test to investigate the question, at the 0.05 level of significance?
Being willing to assume that the distribution of actual birthday lunch times for all employees at the company is approximately normal
Knowing that there are no outliers in the data as indicated by the normal probability plot and boxplot
Using a t-statistic to carry out the test
Using 9 for the number of degrees of freedom
Given that the p-value is greater than 0.05, rejecting the null hypothesis and concluding that the mean time was not greater than 60 minutes.
- 23. Multiple Choice
A dog food company wants to test a new high-protein formula for puppy food to determine whether it promotes faster weight gain than the existing formula for that food. Puppies participating in an experiment will be weighed at weaning and will be weighed at one-month intervals for one year. In designing this experiment, the investigators wish to reduce the variability due to natural differences in puppy growth rates. Which of the following strategies is most appropriate for accomplishing this?
Block on dog breed and randomly assign puppies to existing and new formula groups within each breed.
Block on geographic location and randomly assign puppies to existing and new formula groups within each geographic area.
Stratify on dog breed and randomly sample puppies within each breed. Then assign puppies by breed to either the new or existing formula.
Stratify on geographic location and randomly sample puppies within each geographic area. Then assign puppies by geographic area to either the new or existing formula.
Stratify on gender and randomly sample puppies within gender groups. Then assign puppies by gender to either the new or existing formula.
- 24. Multiple Choice
A student wants to compare the mean times needed to access flight information for two major airlines. 20 randomly selected students accessed one airline's Web site, and the time required to locate the flight information had a mean of 2.5 minutes and a standard deviation of 0.8 minute. 20 different randomly selected students accessed the other airline's Website, and the time required to locate the flight information on that site had a mean of 2.1 minutes and a standard deviation of 1.1 minutes. Assuming that the conditions for inference are met, which of the following statements about the p-value is true?
The p-value is less than 0.01; therefore, there is a significant difference in mean search times on the two Websites
The p-value is greater than 0.01 but less than 0.05; therefore, there is a significant difference in mean search times on the two Websites
The p-value is greater than 0.05 but less than 0.10; therefore, there is a significant difference in mean search times on the two Websites
The p-value is greater than 0.10; therefore, there is no significant difference in mean search times on the two Websites
Since this is a matched-pairs situation, additional information is needed to perform a test of significance.
- 25. Multiple Choice
The histogram represents data obtained after a census of an entire population. The sampling distribution of the sample mean based on samples of size 2 were simulated, and a histogram of the results was produced. Which of the following histograms is most likely the histogram of that sampling distribution?
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