Anais is organizing her rock collection and places each rock in one of three categories: small, medium, or large. This illustrates what level of measurement?

Select one:

a. nominal

b. ordinal Correct

c. interval

d. ratio

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Which of the following is an example of a nominal variable?

Select one:

a. age Incorrect

b. gender

c. height

d. IQ

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What sort of data are temperature measurements?

Select one:

a. interval

b. nominal Incorrect

c. ordinal

d. ratio

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Based on the graph, which statement best describes the relationship between daily high temperatures and the number of people going to the beach?

Text

Select one:

a. There is no relationship.

b. It is a positive linear relationship. Incorrect

c. It is a negative linear relationship.

d. It is a curvilinear relationship.

Question 5

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The table shows the number of train tickets Carl purchased to each station over the last month and the fare to each station. What was the average cost per ride?

Select one:

a. $3.60

b. $4.15

c. $5.45 Correct

d. $5.80

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The outcomes observed in an experiment are: 2, 8, 3, 10, 4, and 9. What is the sample variance?

Select one:

a. 4.1

b. 7.6 Incorrect

c. 9.3

d. 11.6

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Jason collects information about annual family income from each student at his college. He computes both the mean and median family income across all students and is surprised to find that the mean income is much higher than the median income. What is the most likely reason for the difference in the mean and the median?

Select one:

a. The sample size is too small.

b. The median tends to produce lower estimates of central tendency.

c. The median is not an appropriate estimate for annual family income's level of measurement. Incorrect

d. The mean is more affected by a small number of extreme values.

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An instructor administers a test to a class of 30 students and observes that the scores are close to normally distributed with a mean score of 40 and a standard deviation of 10. What can you conclude from these results?

Select one:

a. Approximately 2/3 of the class scored between 30 and 50 on the test.

b. The lowest score on the test was 30 and the highest score was 50.

c. Students found the test to be difficult. Incorrect

d. The average student scored at the 40th percentile.

Question 9

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Laura's quiz scores during the semester were 87, 82, 90, 92, and 84. What was her mean score?

Select one:

a. 79

b. 84

c. 86

d. 87 Correct

Question 10

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The table lists the populations and relative frequencies of car ownership in four neighboring cities. Which city has the most cars?

Select one:

a. Northland

b. Southland Incorrect

c. Eastville

d. Westville

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In the figure shown, Sample A and Sample B have the same

Text

Select one:

a. median.

b. quartiles. Incorrect

c. range.

d. variance.

Question 12

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The contingency table describes the living arrangements of students at a small college. What percentage of the students are women who live in off-campus housing?

Select one:

a. 21

b. 23

c. 54 Correct

d. 44

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Which of these correlation coefficients shows the strongest linear relationship between two variables?

Select one:

a. -0.31

b. -0.22

c. +0.14 Incorrect

d. +0.20

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What conclusion can be drawn from the graph of average daily temperature and hot beverage sales?

Text

Select one:

a. There is a negative correlation between average daily temperature and hot beverage sales.

b. There is a positive correlation between average daily temperature and hot beverage sales. Incorrect

c. There is a curvilinear correlation between average daily temperature and hot beverage sales.

d. There is no correlation between average daily temperature and hot beverage sales.

Question 15

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The coefficient of correlation r is a measure of statistical relationships that are

Select one:

a. causal.

b. linear. Correct

c. positive.

d. significant.

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A bag contains marbles of different colors (red, yellow, and blue) and different sizes (small and large). The probability of picking a blue marble out of the bag is 0.10 and the probability of picking a large marble is 0.50. What is the probability of picking a large blue marble?

Select one:

a. 0.05

b. 0.10

c. 0.50

d. 0.60 Incorrect

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A swimmer, Sarah, hopes to compete in an upcoming meet. There are 8 team members eligible for the breaststroke event at the meet, but only 1 team member will be randomly selected to compete in that event. There are 4 team members eligible for the butterfly event at the meet, but only 1 team member will be randomly selected to compete in that event. Sarah is eligible to compete in both events. What is her chance of being selected for at least one of the two events?

Select one:

a. 1 in 4 Incorrect

b. 1 in 8

c. 3 in 8

d. 3 in 12

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The graduating class of a small college has 170 men and 195 women. If grades and gender are independent, what is the probability that the students with the two highest grade averages will both be women?

Select one:

a. 0.28

b. 0.34

c. 0.37 Incorrect

d. 0.53

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A high school student applies to both the Naval Academy and West Point. The diagram shows his chances of being accepted to each school and the chance that he will be accepted to both. What is the probability that he will be accepted to at least one of the two schools?

Select one:

a. 1%

b. 16%

c. 17% Incorrect

d. 18%

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Which type of data would have a discrete probability distribution?

Select one:

a. number of children per household in a census

b. temperatures recorded at a weather station over a one-year period Incorrect

c. radiation readings at a nuclear power plant

d. repeated measurements of an athlete's distance in the long jump

Question 21

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A video game got a thumbs-up rating from 400 out of 1000 customers surveyed. The customers included 250 women. Assuming that gender does not have any influence on the rating, what is the chance that any randomly selected participant will be a woman who gave the game a thumbs-up rating?

Select one:

a. 10%

b. 16%

c. 25% Correct

d. 65%

Question 22

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A dining guide reviewed all of the restaurants in a town. Only 6 restaurants received a four-star rating. Seventeen 17 received three stars; 18 received two stars; and 9 received a one-star rating. Based on this information, what is the probability of a restaurant receiving a four-star rating?

Select one:

a. 0.05

b. 0.06

c. 0.10

d. 0.12 Correct

Question 23

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The table shows the likelihood that a team will score a certain number of touchdowns in a football game. What is the probability that a team will score at least 2 touchdowns?

Select one:

a. 0.36

b. 0.47 Incorrect

c. 0.49

d. 0.64

Question 24

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The mean score on a college entrance exam is 1200, and the standard deviation is 100. If the scores are normally distributed, what is the likelihood of a score greater than 1450?

Select one:

a. 0.0062

b. 0.0091

c. 0.0124 Incorrect

d. 0.0025

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What type of distribution is depicted in the graph?

Text

Select one:

a. bimodal Incorrect

b. discrete

c. normal

d. uniform

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A school gives an exam for which the scores are normally distributed. What proportion of students will score within 2.3 standard deviations of the mean?

Select one:

a. 0.72 Incorrect

b. 0.84

c. 0.89

d. 0.98

Question 27

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The mean score for 18 holes of golf on the Parkvale municipal course is 68, with a standard deviation of 12. Lou scores 95. What z-score does this correspond to?

Select one:

a. 1.40 Incorrect

b. 1.79

c. 2.25

d. 2.70

Question 28

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Damien determines that the differences he found in his study are statistically significant at the 0.05 level of significance. What is the correct interpretation of this finding?

Select one:

a. 95% of the study participants achieved the level of performance expected.

b. There is a 95% chance that the observed differences are not correct.

c. We can expect that there will be no observable differences 5% of the time. Incorrect

d. If the study were repeated 100 times, we would expect to find the observed differences 95 times.

Question 29

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The central limit theorem says that if the sample size doubles, the sampling distribution of the sample mean will

Select one:

a. exhibit greater dispersion.

b. approach a normal distribution. Correct

c. be positively skewed.

d. become more variable.

Question 30

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Scores on a certain standard achievement test are normally distributed with mean =100 and standard deviation =10. If you take multiple samples of size 16, what percent of sample of means will be between 95 and 105?

Select one:

a. 68.3%

b. 69.2% Incorrect

c. 95.4%

d. 99.9%

Question 31

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A student performed a chi-square test with 5 degrees of freedom. What would be the critical value of the chi-squared statistic, assuming a significance level of p<0.05?

Select one:

a. 1.96

b. 5.01 Incorrect

c. 9.24

d. 11.07

Question 32

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When drawn from a normal distribution, 95% of the sample means will fall within how many standard deviations of the population mean?

Select one:

a. 1.44

b. 1.96

c. 2.25 Incorrect

d. 2.58

Question 33

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A maple syrup manufacturer asks 100 consumers to rate its brand of maple syrup on a scale of 1 to 10. The mean rating was 7, with a sample standard deviation of 1.5. Based on this sample, what is the 95% confidence interval for the estimate of the population mean?

Select one:

a. (4.4, 9.6)

b. (4.7, 9.3)

c. (5.2, 8.8) Incorrect

d. (6.7, 7.3)

Question 34

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A regression analysis suggests that the number of children an employee has predicts the number of personal days he/she will take off of work. The slope of the regression line is 3.2, and the lower bound of the confidence interval for this slope is 0.8. What is the upper bound?

Select one:

a. 4.0

b. 4.2

c. 5.2

d. 5.6 Correct

Question 35

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A coach wishes to determine whether her basketball team is performing worse this year than in previous years. The coach knows that over the past several years' games, the team scored an average of 84 points. In the last year, with 36 games, they scored an average of only 71 points, with a standard deviation of 24 points. What t-test statistic does this score correspond to?

Select one:

a. -3.25 Correct

b. -2.17

c. -1.75

d. -0.54

Question 36

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In a statistical analysis, how does the t-distribution differ from the z-distribution?

Select one:

a. It has a smaller standard deviation.

b. It does not assume normality.

c. It depends on sample size. Correct

d. It is a discrete distribution.

Question 37

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In hypothesis testing, a Type I error occurs when

Select one:

a. a chance result is reported as statistically significant. Correct

b. a researcher mistakenly accepts the null hypothesis.

c. the study lacks statistical power to detect an effect.

d. the wrong statistical significance threshold is chosen.

Question 38

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An analyst predicts that clients who used a certain investment strategy will have below-average profits . With a sample of 21 clients, the analyst performs a one-tailed t-test of this hypothesis at the 95% confidence level, resulting in a t-statistic of -1.65. How should the analyst interpret the result?

Select one:

a. Other investment strategies worked better.

b. The result was statistically significant.

c. The null hypothesis is not rejected. Correct

d. A Type I error has occurred.

Question 39

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A researcher tests the hypothesis that math scores are significantly different between two groups of students. The test yields a p-value of 0.01. What is the correct interpretation of this value?

Select one:

a. There is a 1% likelihood that the difference was due to chance.

b. The two score distributions have common values 1 percent of the time.

c. The result has a 99% probability of being replicated. Incorrect

d. The test results were 99% different between the two groups.

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A class of 25 students took a reading test before and after completing an intensive vocabulary course to determine whether there was a change in scores in either direction. The mean pre-test score was 24, and the mean post-test score was 32. The standard deviation of the difference was 9. What value of the t-statistic does this difference correspond to?

Select one:

a. 1.7

b. 2.9 Incorrect

c. 4.4

d. 5.6

Question 41

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A researcher wants to test the hypothesis that right-handed people will have different visual acuity in their left and right eyes. What sort of test should the researcher use?

Select one:

a. one-tailed test with two dependent samples

b. one-tailed test with two independent samples

c. two-tailed test with two dependent samples

d. two-tailed test with two independent samples Incorrect

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To test the effectiveness of a new therapy, a researcher compares the health outcomes of 45 patients who receive the therapy and 38 patients in a control condition. In a two-tailed test, the researcher obtains a t-statistic of 1.83. What is the strictest threshold at which this result could be considered significant?

Select one:

a. P<0.1

b. P<0.05 Incorrect

c. P<0.01

d. P<0.001

Question 43

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A researcher is conducting a study comparing the effects of drug treatments on hours of sleep across three groups. Group 1 is taking Drug A, Group 2 is taking Drug B, and Group 3 is a control group not taking any drug. What statistic would be most appropriate to compare the mean number of hours of sleep across the three groups?

Select one:

a. paired samples t test

b. independent t test

c. analysis of variance

d. factor analysis Incorrect

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What does the denominator represent in the formula for an F-statistic used in an ANOVA?

Select one:

a. effect size of the experimental treatment

b. grand mean across all observations Incorrect

c. one minus the number of observations

d. variation within treatment groups

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What is one way that the F-statistic differs from the t-statistic

Select one:

a. It can never be negative.

b. It has a continuous distribution.

c. It depends on degrees of freedom.

d. It has a symmetric distribution. Incorrect

Question 46

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According to the ANOVA test, which statement is true if the variation of treatment means from the grand mean is much larger than the variation within treatment groups?

Select one:

a. The risk of Type II error is increased.

b. The sample size may be too small.

c. The treatment groups have different means. Correct

d. The samples have overlapping distributions.

Question 47

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Five players on a basketball team score a total of 85 points in a game. An analyst performs a chi-square test to find out whether the five players' point totals differ significantly from one another. According to the null hypothesis, how many points would each player be expected to score?

Select one:

a. 0

b. 9

c. 13

d. 17 Correct

Question 48

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The table shows the areas of study chosen by freshmen at a liberal arts college over the last 50 years. The admissions office compares the choices of this year's incoming freshmen to these rates using a chi-square test, with a significance threshold of p<0.01. What is the critical value of the test statistic?

Select one:

a. 7.8

b. 9.2

c. 13.3 Correct

d. 15.1

Question 49

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The table shows the areas of study chosen by freshmen at a liberal arts college over the last 50 years. This year's freshmen class has 500 students. If students' choices this year reflect the historical averages, how many freshmen would be expected to major in the social sciences?

Text

Select one:

a. 115 Incorrect

b. 140

c. 165

d. 170

Question 50

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A researcher uses linear regression to analyze the association between people's ages in years and their score on a depression scale. Age is the independent variable in the model, and the number of points on the depression scale is the dependent variable. The mean age is 58, the mean depression score is 7, and the slope of the regression line is 0.2. Based on the regression model, what is the expected depression score of a 72-year-old?

Select one:

a. 7.2

b. 9.8 Correct

c. 11.3

d. 14.0

Question 51

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A researcher is studying the relationship between academic and sports performance in 100 college athletes. She runs a regression model with number of games started as the independent variable and grade point average as the dependent variable. This model yields a slope of b=-0.3. A two-tailed test of this estimate produces a t-statistic of -2.1. Assuming a significance threshold of p<0.05, how should the researcher interpret the results?

Select one:

a. Each additional game played is associated with a 0.3 point decline in GPA.

b. 30% of the variation in GPA can be explained by the number of games played.

c. Grade point average and number of games played are positively associated. Incorrect

d. There is no reliable association between GPA and number of games played.

Question 52

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A sociologist wants to examine academic performance across grade levels in an elementary school. The number of students is not the same in each grade. Which sampling method would be most appropriate?

Select one:

a. simple random sampling

b. systematic random sampling

c. stratified random sampling Correct

d. cluster sampling

Question 53

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A researcher asks children to complete a math test. Half of the children are told they will be rewarded for every correct answer; the others will receive no reward. The researcher will compare the mean test scores for the two groups. What type of research design is this?

Select one:

a. Census

b. Experiment

c. Observational study Incorrect

d. Survey

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Simple random sampling is used in various study designs to allow for

Select one:

a. greater variety in outcome values. Incorrect

b. targeted samples of specific subgroups.

c. a sample that is representative of its population.

d. greater statistical significance levels.

Question 55

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To increase the generalizability of a study's results, participants must be

Select one:

a. approximately the same age.

b. blinded to the purpose of the research.

c. observed multiple times.

d. representative of the population of interest. Correct

Question 56

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In research studies, which situation demonstrates self-selection bias?

Select one:

a. In an online survey on gun control, gun owners were twice as likely to respond as non-owners.

b. For a statewide poll, a newspaper only contacted residents of urban areas. Incorrect

c. In an aging study, men were more likely than women to die before study completion.

d. In an experiment, most of the female participants were assigned to the control group by chance.

Question 57

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A guidance counselor wants to administer a survey to students in her school. Why might she choose stratified sampling over simple random sampling?

Select one:

a. To reduce the chance of self-selection bias in the sample.

b. To ensure that students from all grades are represented. Correct

c. To account for the school's relatively small population size.

d. To increase the total response rate for the survey.

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What is the best way to decide which subjects should be placed in control and treatment groups in an experiment?

Select one:

a. order of enrollment

b. pre-screening Incorrect

c. random assignment

d. self-selection

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Besides random selection, which study design increases the generalizability of survey results?

Select one:

a. allowing open-ended responses

b. increasing the sample size

c. offering a monetary incentive Incorrect

d. using an in-person interview format

Question 60

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In a research study, what type of research design is most appropriate for establishing causality?

Select one:

a. between-subjects

b. experimental Correct

c. observational

d. survey