2.In a geology course, students were learning to use a balance scale to make accurate weighings of rock samples. One student plans to weigh a rock 20 times and then calculate the average of the 20 measurements to estimate her rock's true weight. A second student plans to weigh a rock 5 times and calculate the average of the 5 measurements to estimate his rock's true weight. Which student is more likely to come the closest to the true weight of the rock he or she is weighing?

A.The student who weighed the rock 20 times.

B.The student who weighed the rock 5 times.

C.Both averages would be equally close to the true weight.

3.

Suppose half of all newborns are girls and half are boys. Hospital A, a large city hospital, records an average of 50 births a day. Hospital B, a small, rural hospital, records an average of 10 births a day. On a particular day, which hospital islesslikely to record 80% or more female births?

A.Hospital A (with 50 births a day), because the more births you see, the closer the proportions will be to .5.

B.Hospital B (with 10 births a day), because with fewer births there will be less variability.

C.The two hospitals are equally likely to record such an event, because the probability of a boy does not depend on the number of births.

4.A random sample of 25 college statistics textbook prices is obtained and the mean price is computed. To determine the probability of finding a more extreme mean than the one obtained from this random sample, you would need to refer to:

A.the population distribution of all college statistics textbook prices.

B.the distribution of prices for this sample of college statistics textbooks.

C.the sampling distribution of textbook prices for all samples of 25 textbooks from this population.

5.Consider the distribution of average number of hours that college students spend sleeping each weeknight. This distribution is very skewed to the right, with a mean of 5 and a standard deviation of 1. A researcher plans to take a simple random sample of 18 college students. If we were to imagine that we could take all possible random samples of size 18 from the population of college students, the sampling distribution of average number of hours spent sleeping will have a shape that is

A.Exactly normal.

B.Less skewed than the population.

C.Just like the population (i.e., very skewed to the right).

D.It's impossible to predict the shape of the sampling distribution.

6.Imagine you have a huge jar of candies that are a generic version of M&Ms. We know that 40% of the candies in the jar are brown. Imagine that you create a sample by randomly pulling 20 candies out of the jar. If you repeated this 10 times to create 10 samples, each with 20 candies, about how many browns would you expect to find in each of the 10 samples?

A.Each sample would have exactly 8 brown candies.

B.Most of the samples would have 0 to 8 brown candies.

C.Most of the samples would have 8 to 20 brown candies.

D.Most of the samples would have 6 to 10 brown candies.E.You are just as likely to get any count of brown candies between 0 and 20.

9.Two different samples will be taken from the same population of test scores where the population mean and standard deviation are unknown. The first sample will have 25 data values, and the second sample will have 64 data values. A 95% confidence interval will be constructed for each sample to estimate the population mean. Which confidence interval would you expect to have greater precision (a smaller width) for estimating the population mean?

A.I expect the confidence interval based on the sample of 64 data values to be more precise.

B.I expect both confidence intervals to have the same precision.

C.I expect the confidence interval based on the sample of 25 data values to be more precise.

10.A 95% confidence interval is computed to estimate the mean household income for a city. Which of the following values will definitely be within the limits of this confidence interval?

A.The population mean

B.The sample mean

C.The standard deviation of the sample meanD.None of the above

11.Each of the 110 students in a statistics class selects a different random sample of 35 Quiz scores from a population of 5000 scores they are given. Using their data, each student constructs a 90% confidence interval for the average Quiz score of the 5000 students. Which of the following conclusions is correct?

A.About 10% of the sample means will not be included in the confidence intervals.

B.About 90% of the confidence intervals will contain .

C.It is probable that 90% of the confidence intervals will be identical.

D.About 10% of the raw scores in the samples will not be found in these confidence intervals.

12.A 95% confidence interval for the mean reading achievement score for a population of third grade students is (43, 49). The margin of error of this interval is:

A.5

B.3

C.6

13.Justin and Hayley conducted a mission to a new planet, Planet X, to study arm length. They took a random sample of 100 Planet X residents and calculated a 95% confidence interval for the mean arm length. What does a 95% confidence interval for arm length tell us in this case? Select the best answer:

A.I am 95% confident that this interval includes the sample mean () arm length.

B.I am confident that most (95%) of all Planet X residents will have an arm length within this interval.

C.I am 95% confident that most Planet X residents will have arm lengths within this interval.

D.I am 95% confident that this interval includes the population mean arm length.

14.Suppose that a random sample of 41 state college students is asked to measure the length of their right foot in centimeters. A 95% confidence interval for the mean foot length for students at this university turns out to be (21.709, 25.091). If instead a 90% confidence interval was calculated, how would it differ from the 95% confidence interval?

A.The 90% confidence interval would be narrower.

B.The 90% confidence interval would be wider.

C.The 90% confidence interval would be the same as the 95% confidence interval.

15.

A pollster took a random sample of 100 students from a large university and computed a confidence interval to estimate the percentage of students who were planning to vote in the upcoming election. The pollster felt that the confidence interval was too wide to provide a precise estimate of the population parameter. What could the pollster have done to produce a narrower confidence interval thatwould produce a more precise estimate of the percentage of all university students who plan to vote in the upcoming election?

A.Increase the sample size to 150.

B.Increase the confidence level to 99%.

C.Both a and b

D.None of the above

16.A newspaper article states with 95% confidence that 55% to 65% of all high school students in the United States claim that they could get a hand gun if they wanted one. This confidence interval is based on a poll of 2000 high school students in Detroit. How would you interpret the confidence interval from this newspaper article?

A.95% of large urban cities in the United States have 55% to 65% high school students who could get a hand gun.

B.If we took many samples of high school students from different urban cities, 95% of the samples would have between 55% and 65% high school students who could get hand guns.

C.You cannot use this confidence interval to generalize to all teenagers in the United States because of the way the sample was taken.

D.We can be 95% confident that between 55% and 65% of all United States high school students could get a hand gun.

QUESTION 17

The Gallup poll (August 23, 2002) reported that 53% of Americans said they would favor sending American ground troops to the Persian Gulf area in an attempt to remove Hussein from power. The poll also reported that the "margin of error" for this poll was 4%. What does the margin of error of 4% indicate?

A.There is a 4% chance that the estimate of 53% is wrong.

B.The percent of Americans who are in favor is probably higher than 53% and closer to 57%.

C.The percent of Americans who are in favor is estimated to be between 49% and 57%.

QUESTION 18

Suppose two researchers want to estimate the proportion of American college students who favor abolishing the penny. They both want to have about the same margin of error to estimate this proportion. However, Researcher 1 wants to estimate with 99% confidence and Researcher 2 wants to estimate with 95% confidence. Which researcher would need more students for her study in order to obtain the desired margin of error?

A.Researcher 1.

B.Researcher 2.

C.Both researchers would need the same number of subjects

.D.It is impossible to obtain the same margin of error with the two different confidence levels.

QUESTION 19

The makers of Mini-Oats cereal have an automated packaging machine that is set to fill boxes with 24 ounces of cereal. At various times in the packaging process, a random sample of 100 boxes is taken to see if the machine is filling the boxes with an average of 24 ounces of cereal. Which of the following is a statement of the null hypothesis being tested?

A.The machine is filling the boxes with the proper amount of cereal.

B.The machine is not filling the boxes with the proper amount of cereal.

C.The machine is not putting enough cereal in the boxes.

QUESTION 20

A research article gives a p-value of .001 in the analysis section. Which definition of a p-value is the most accurate?

A.the probability that the observed outcome will occur again.

B.the probability of observing an outcome as extreme or more extreme than the one observed if the null hypothesis is true.

C.the value that an observed outcome must reach in order to be considered significant under the null hypothesis.

D.the probability that the null hypothesis is true.

QUESTION 21

If a researcher was hoping to show that the results of an experiment were statistically significant they would prefer:

A.a large p-value

B.a small p-value

C.p-values are not related to statistical significance

QUESTION 22

A researcher compares men and women on 100 different variables using a two-sample t-test. He sets the level of significance to .05 and then carries out 100 independent t-tests (one for each variable) on these data. If, for each test, the null hypothesis actually is true, about how many "statistically significant" results will be produced?

A.0

B.5

C.10

D.none of the above

QUESTION 25

A newspaper article claims that the average age for people who receive food stamps is 40 years. You believe that the average age is less than that. You take a random sample of 100 people who receive food stamps, and find their average age to be 39.2 years. You find that this is significantly lower than the age of 40 stated in the article (p < .05). What would be an appropriate interpretation of this result?

A.The statistically significant result indicates that the majority of people who receive food stamps is younger than 40.

B.Although the result is statistically significant, the difference in age is not of practical importance.

C.An error must have been made. This difference is too small to be statistically significant.

QUESTION 27

A researcher conducts an experiment on human memory and recruits 15 people to participate in her study. She performs the experiment and analyzes the results. She obtains a p-value of .17. Which of the following is a reasonable interpretation of her results?

A.This proves that her experimental treatment has no effect on memory.

B.There could be a treatment effect, but the sample size was too small to detect it.

C.She should reject the null hypothesis.

D.There is evidence of a small effect on memory by her experimental treatment.

QUESTION 26

A newspaper article stated that the US Supreme Court received 812 letters from around the country on the subject of whether to ban cameras from the courtroom. Of these 812 letters, 800 expressed the opinion that cameras should be banned. A statistics student was going to use this sample information to conduct a test of significance of whether more than 95% of all American adults feel that cameras should be banned from the courtroom. What would you tell this student?

A.This is a large enough sample to provide an accurate estimate of the American public's opinion on the issue.

B.The necessary conditions for a test of significance are not satisfied, so no statistical test should be performed.

C.With such a large number of people favoring the notion that cameras be banned, there is no need for a statistical test.

QUESTION 28

It is reported that scores on a particular test of historical trivia given to high school students are approximately normally distributed with a mean of 85. Mrs. Rose believes that her 5 classes of high school seniors will score significantly better than the national average on this test. At the end of the semester, Mrs. Rose administers the historical trivia test to her students. The students score an average of 89 on this test. After conducting the appropriate statistical test, Mrs. Rose finds that the p-value is .0025. Which of the following is the best interpretation of the p-value?

A.A p-value of .0025 provides strong evidence that Mrs. Rose's class outperformed high school students across the nation.

B.A p-value of .0025 indicates that there is a very small chance that Mrs. Rose's class outperformed high school students across the nation.

C.A p-value of .0025 provides evidence that Mrs. Rose is an exceptional teacher who was able to prepare her students well for this national test.

QUESTION 29

In the country of United States, the height measurements of ten-year-old children are approximately normally distributed with a mean of 53.6 inches, and standard deviation of 2.1 inches. What is the probability that a randomly chosen child has a height of less than 50.45 inches?

(Hint:Using technology such as theNormal Curve Calculatoris recommended.)

A.0.567

B.0.894

C.0.933

D.0.067

QUESTION 30

You want to estimate the average number of songs college students store on their portable devices. You want the margin of error to be no more than plus or minus 20 songs. You want a 95% confidence interval. How many students should you sample? Assume the standard deviation is 148 songs.

(Hint:Use of theConfidence Intervals(XLS)Templateis recommended.)

A.15 students

B.20 students

C.211 students

D.150 students

QUESTION 31

In a survey of 1389 adults from India, 668 say they are confident that the food they eat in their country is safe.Construct a 90% confidence interval for the population proportion of adults who feel that the food they eat is safe.

(Hint:Use of theConfidence Intervals (XLS)Templateis recommended.)

A.(0.459, 0.505)

B.(0.495, 0.517)

C.(0.464, 0.498)

D.(0.474, 0.508)

QUESTION 33

A regression was run to determine if there is a relationship between hours of TV watched per day (x) and number of sit-ups a person can do (y).The results of the regression were:

y=-0.621x+35.997withr=-0.801

Use this to predict the number of sit-ups a person who watches 2 hours of TV per day can do (to the nearest whole number).

A.30

B.34

C.36

D.38

QUESTION 34

Food inspectors inspect samples of food products to see if they are safe. This can be thought of as a hypothesis test with the following hypotheses.

H₀: the food is safe

H_a: the food is not safe

The following is an example of what type of error?

The sample suggests that the food is safe, but it actually is not safe.

A.Type I Error

B.Type II Error

C.Not an Error

D.Type Iand Type II Errors

QUESTION 35

In a survey, 25 people were asked how much they spent on their child's last birthday gift.The results were roughly bell-shaped with a mean of $41 and a standard deviation of $5.Find the margin of error,E, at a 90% confidence level.

(Hint:Use of theConfidenceIntervals(XLS)Templateis recommended.)

A.1.711

B.1.645

C.1.28

D.0.9

QUESTION 36

A used car dealer says that the mean price of a 2008 Honda CR-V is $20,500.You suspect this claim is incorrect and find a random sample of 14 similar vehicles with a mean price of $19,850 and a standard deviation of $1084.At a 5% level of significance,is there enough evidence to reject the dealer's claim?

(Hint:Use of theHypothesis Test(XLS)Templateis recommended.)

A.SinceP>0.05,wefail to reject the null and therefore we can't support the claim that the mean price of a 2008 Honda CR-V is $20,500.

B.SinceP>0.05, wefail to reject the null and therefore we can support the claim that the mean price of a 2008 Honda CR-V is $20,500.

C.SinceP<0.05, wereject the null and therefore we can support the claim that the mean price of a 2008 Honda CR-V is $20,500.

D.SinceP <0.05,

QUESTION 37

The line of best fit through a set of data is:y=56.428+2.497x

According to this equation, what is the predicted value (to the nearest tenth) of the dependent variable,y,when the independent variable,x, has a value 180?

A.500.6

B.505.9

C.49.5

D.50.5

QUESTION 39

Child Health and Development Studies (CHDS) has been collecting data about expectant mothers in Oakland, CA since 1959. One of the measurements taken by CHDS is the weight increase (in pounds) for expectant mothers in the second trimester. In a fictitious study, suppose that CHDS finds the average weight increase in the second trimester is 14 pounds. Suppose also that, in 2015, a random sample of 40 expectant mothers have mean weight increase of 16 pounds in the second trimester, with a standard deviation of 6 pounds. At the 5% significance level, we can conduct a one-sided T-test to see if the mean weight increase in 2015 is greater than 14 pounds. Statistical software tells us that the p-value = 0.021.

Which of the following is the most appropriate conclusion?

A.Since the p-value is greater than the significance level, we have sufficient evidence to reject the null hypothesis that the true mean weight is still 14 lbs.

B.Since the p-value is less than the significance level, we have sufficient evidence to reject the null hypothesis that the true mean weight is still 14 lbs.

C.Since the p-value is less than the significance level, we do not have sufficient evidence and, therefore, fail to reject the null hypothesis that the true mean weight is still 14 lbs.

D.Since the p-value is greater than the significance level, we do not have sufficient evidence and, therefore, fail to reject the null hypothesis that the true mean weight is still 14 lbs.

QUESTION 40

Confidence interval precision: We know that narrower confidence intervals give us a more precise estimate of the true population proportion. Which of the following could we do to produce higher precision in our estimates of the population proportion?

A.We can select a lower confidence level and decrease the sample size.

B.We can select a higher confidence level and increase the sample size.

C.We can select a higher confidence level and decrease the sample size.

D.We can select a lower confidence level and increase the sample size.

QUESTION 41

In a recent ABC News/Washington Post poll, 1,016 adults nationwide answered the question, "Overall, do you support or oppose allowing gays and lesbians to marry legally?"Of the respondents, 619 support same-sex marriage. What is the 95% confidence interval for the proportion of all American adults who support same-sex marriage?

Optional:ConfidenceIntervals.xlsx

A.(0.570, 0.648)

B.(0.584, 0.634)

C.(0.579, 0.639)

D.(0.594, 0.624)

QUESTION 42

In a study of migrating Sandhill Cranes, the distance traveled in a day were normally distributed, with a mean of 267 kilometers and a standard deviation of 86 kilometers.Find the probability that the distance traveled in a day by a randomly selected Sandhill Crane from the study is greater than 500 kilometers. (Use appropriate technologyhereor the Standard Normal Distribution Table to find your answer)

A.0.2709

B.0.2710

C.0.0034

D.0.9966

QUESTION 43

1. The table shows the number (in thousands) of earned degrees by level and gender conferred in the US in a recent year:
3. Male
4. Female
5. Total
6. Associate's
7. 361
8. 581
9. 942
10. Bachelor's
11. 734
12. 982
13. 1716
14. Master's
15. 292
16. 439
17. 731
18. Doctoral
19. 80
20. 84
21. 164
22. Total
23. 1467
24. 2086
25. 3553
26. A person who earned a degree in a year is randomly selected.Find the probability of selecting someone who earned an associate's degree, given that the person is male,P(Associate's Degree | Male).
27. A.361/1467
28. B.361/3553
29. C.942/1467
30. D.1467/3553

QUESTION 44

A random sample of 15 statistics textbooks has a mean price of $100 with a standard deviation of $31.75. Determine whether a normal distribution or at- distribution should be used or whether neither of these can be used to construct a confidence interval. Assume the distribution of statistics textbook prices is not normally distributed.

A.Use normal distribution.

B.Cannot use normal distribution ort-distribution.

C.Use the t-distribution.

45..The median list price of homes for sale in Erie County in May 2017 was $164,000 and the median list price of homes for sale in May 2018 was $169,000. Therefore, the percent of increase in the median list price was 3%, approximately.

Please select the true statement below.

A.For any home that was for sale in Erie County from May 2017 to May 2018, the percent of increase in the list price of that home was 3%, approximately.

B.The median list price of homes that were for sale in Erie County from May 2017 to May 2018 was increased by 3%, approximately, but we can't conclude the same increase about any particular home that was for sale in Erie County in the period from May 2017 to May 2018.

QUESTION 46

The U.S. Department of Agriculture claims that the mean cost of raising a child from birth to age 2 by husband-wife families in the U.S. is $11,120. A random sample of 400 children (age 2) has a mean cost of $11,225 with a standard deviation of $1645. At= 0.10, determine if there is enough evidence toreject the claim.Which of the following hypothesis tests is set up correctly with the correct outcome regarding the claim?

(Hint:Use of theHypothesis Test(XLS)Templateis recommended.)

Or you may use the Minitab 17 session window output information (shown below) if needed.

Minitab 17 (Session Window)

One-Sample Z

Test of = 11120 vs 11120

The assumed standard deviation = 1645

NMeanSEMean90%CIZP

40011225.082.3(11089.7, 11360.3)1.280.202

A.

We fail to reject the null, and therefore retain the claim that the mean cost of raising a child from birth to age 2 by husband-wife families in the U.S. is $11,120, since z=1.28 and does not fall into the rejection region.

B.

We fail to reject the null, and therefore retain the claim that the mean cost of raising a child from birth to age 2 by husband-wife families in the U.S. is $11,120, since z=1.28, which falls into the rejection region.

C.

We reject the null, and therefore retain the claim that the mean cost of raising a child from birth to age 2 by husband-wife families in the U.S. is not $11,225, since z=1.28 and does not fall into the rejection region.

D.

We reject the null, and therefore retain the claim that the mean cost of raising a child from birth to age 2 by husband-wife families in the U.S. is not $11,225, since z=1.28, which falls into the rejection region.