Questions and Answers of Statistics Alive

Professor Testgiver wonders if the order in which questions are put on a test affects the test score. He administers different forms of the same test to three subsets of 10 students in his class. On
More students than not gain weight during their first year of college. A nutritionist wonders if this is due to the type of food served in campus dining centers. She compares the number of pounds
Which of the studies described in the exercises above are probably post hoc studies? Why does this complicate interpretation of the results?
For each of the following studies, writea. A directional research hypothesis,b. A nondirectional research hypothesis, andc. The null hypothesis. A researcher is studying whether the number of
For each of the following studies, writea. A directional research hypothesis,b. A nondirectional research hypothesis, andc. The null hypothesis.A researcher is studying whether the size of the
A camp director is investigating the number of recreational activities that boys sign up to participate in and the number of recreational activities that girls sign up to participate in.
An energy researcher wonders which type of heating—electric, natural gas, or oil—is the fastest in raising the temperature of a room. Eight different-sized rooms of identical construction are
An educational psychologist is investigating whether or not asking questions at the start of each class lecture changes student retention of the subsequent lecture materials.
What will happen to the value of F if the treatment effect increases but the random error stays the same?
Assume the following data for a study:Conduct a Tukey HSD on the ANOVA at α = .05. Between which pair(s) does the statistical significance lie? Group 1 Group 2 Group
You are told that a study is a 3 × 3 ANOVA. Make up variables and conditions and draw a diagram for the study.
You are told that a study is a 3 × 2 × 2 ANOVA. Make up variables and conditions and draw a diagram for the study.
A psychologist conducts a 2 × 3 × 2 ANOVA. How many main effects are possible?
A psychologist conducts a 3 × 5 ANOVA. How many main effects are possible?
A researcher conducts a 3 × 6 ANOVA. How many main effects are possible?
A researcher conducts a 2 × 2 × 4 ANOVA. How many main effects are possible?
A psychologist is studying the effect of the number of hours of television children view and the primary type of program children view on the children’s level of aggression. Here are the mean
A psychologist conducts a 2 × 3 × 2 ANOVA. How many interaction effects can there be?
You read a study that says 36% of college students nationwide change their intended major between their freshman and senior years. You get permission to do an exit poll of your college’s graduating
A psychologist conducts a 3 × 5 ANOVA. How many interaction effects can there be?
LaTawna runs a used textbook business near City University. One semester, she sells 882 used textbooks to City University students. Of these, 387 are for 100-level, 147 for 200-level, 180 for
A researcher conducts a 3 × 6 ANOVA. How many interaction effects are possible?
A researcher conducts a 2 × 2 × 4 ANOVA. How many interaction effects are possible?
A psychology student wonders if underclass students (freshmen and sophomores) differ in their vegetable preference from upper-class students (juniors and seniors). She randomly samples students and
A recent poll of young college women between the ages of 18 and 21 years found that 44% want to marry before they are 25, 32% want to marry between the ages of 25 and 30, 15% want to marry between
The tourism director for an ocean resort town claims that 57% of the adults who visit the area stay in hotels, 26% rent condos, 10% stay in campgrounds, and 7% stay with relatives who live in the
A lakeside food vendor knows from past experience that his sales ratios for lunches are 43% hamburgers, 37% hot dogs, 12% sausage rolls, and 8% veggie burgers. Today he sells 189 lunches. Of those,
You read a report saying that women and men differ in their preferred car colors. What are the two variables in this study?
You read a report saying that the hobbies of same-sex friends are more similar than the hobbies of same-sex classmates. What are the two variables in this study?
You read a report saying that students who take at least a year off from school between high school and college are less apt to drop out than those who go to college directly from high school. What
You read a report saying that those who listen to music before they drift off to sleep tend to be extraverts while those who read books before they drift off to sleep tend to be introverts. What are
Calculate the following:a. When power is 80%, what is the Type II error?b. When Type II error is 12%, what is the power?
Calculate the following:a. When power is 84%, what is the Type II error?b. When Type II error is 25%, what is the power?
A researcher had originally intended to select subjects for placement into treatment groups (i.e., the independent variable) based on a median split of their scores on a placement test for the
A research assistant is helping to collect observational data. However, he is careless in scoring the observations. As a result, dependent variable scores are inaccurate and prone to error.Directions
A popular theory says that the more sugar children eat, the more active they become. To test the theory, a researcher receives permission to adjust the diets of 10 preschool children and monitor
You are designing a study to be evaluated with a two-sample nondirectional independent t test at α = .05. You are able to obtain 25 subjects per group. Approximately what will effect size r have to
Here are the quiz scores of six students on each of three pop quizzes:a. Create three separate scatterplots: Quiz 1 and Quiz 2, Quiz 1 and Quiz 3, and Quiz 2 and Quiz 3.b. Describe the direction and
You are designing a study to be evaluated with a two-sample nondirectional independent t test at α = .05. You are able to obtain 65 subjects per group. Approximately what will Cohen’s d have to be
You calculate a two-sample nondirectional independent t test at α = .05. Your study has 130 subjects per group and effect size r is .20. To the nearest 10%, what is the power of your study?
You calculate a two-sample nondirectional independent t test at α = .05. Your study has 45 subjects per group and Cohen’s d is .60. To the nearest 10%, what is the power of your study?
You calculate a one-way ANOVA at α = .05. Your study has four groups with 30 subjects per group. Effect size η is .30. To the nearest 10%, what is the power of your study?
You calculate a chi-square test of independence at α = .05. Your study has 1 df, 200 total subjects, and effect size ϕ is .19. To the nearest 10%, what is the power of your study?
Gather data from 10 adults (perhaps from students in your statistics class) for height and shoe size.a. Create a scatterplot for the data.b. Describe the direction and apparent strength of the data.
Gather data from 10 adults (perhaps from students in your statistics class) for the number of hours of television watched on an average day and the typical number of hours of sleep obtained in an
The admissions officer of TopNotch University wants to know the relationship between the high school GPAs and college GPAs for the 15 merit scholars in this year’s freshman class. Here are the
The data below are for days of rainfall per week over a 12-week period in a resort area and occupancy rate (percentage of beds filled) for a hotel in the same resort area. Compute the Pearson r
Create a scatterplot of the following heights and weights of ninth-grade girls: Subject Quashonna Ronette Height 66 68 Weight 132 121
Create a scatterplot of the following data on the average annual household income and the average cost of a three-bedroom, 1½-bath home (both to the nearest thousand dollars) in 10 geographic areas:
Create a scatterplot of the following number of times 15 teenage girls look at themselves in a mirror per day and their score on a test of self-esteem (scored 1–10, where higher scores indicate
Create a scatterplot of the following number of hours 12 students spend playing computer games per day and their academic average (in percentage). Student # 1 2 3 4 5 7 8 10 11 12 Hours
The predicted resting heart rate for Diego based on his score on a physical fitness test is 78.5 beats per minute. The standard error of prediction is 2.4 beats per minute. His physician is about to
Assume that the correlation between toddlers’ ages and their play distances from their mothers is +.90. This correlation is very high. What effect will such a high correlation have on the standard
Assume that the psychologist who studied the relationship of toddlers’ age to their play distance now includes additional toddlers who are older than those listed. And assume that these additional
The R2 for a study is .74. What is the residual?
The residual for a study is .19. What is R2?
A researcher reports an R2 of .88 and a residual of 14. Comment on this.
Which of these is preferred—a study with an R2 of .73 or a study with a residual of .27?
The R2 for a study with three predictors is .64. If the researcher drops one of the predictors and reruns the study, what should happen to the R2?
The R2 for a study with three predictors is .64. If the researcher adds a fourth predictor, what should happen to the R2?
The R2 for a study with three predictors is .64. If the researcher changes the order of the three predictors, what should happen to the R2?
A prior study examined the correlation between the number of times per day teenage girls look at themselves in the mirror and those girls’ level of self-esteem. The correlation was +0.612. The
Assume that you are studying the effect of noise level on memory. Your study involves manipulating the level of noise while subjects try to memorize a list of words and then measuring the number of
Sketch overlapping normal curves for a three-group ANOVA. Locate and mark a score X at any point in Group 1. Then, using symbols, indicate that score’sa. Total deviation,b. Within-group deviation,
If the total deviation is 683.78 and the within-group deviation is 457.52, what is the between-group deviation?
If the within-group deviation is 348.76 and the between-group deviation is 872.45, what is the total deviation?
If the between-group deviation is 245.22 and the within-group deviation is 106.33, what is the total deviation?
If the total deviation is 492.56 and the between-group deviation is 306.55, what is the within-group deviation?
You calculate F and get a value of +0.89. Is that value possible? Will it be statistically significant?
You calculate F and get a value of −0.23. Comment on this.
If MSbet = 100 and MSwith = 25, what is F?
If MSbet = 800 and MSwith = 380, what is F?
If MSbet = 500 and F is 2.00, what is MSwith?
If MSbet = 300 and F is 3.00, what is MSwith?
If MSwith = 400 and F is 2.00, what is MSbet?
If MSwith = 200 and F is 3.00, what is MSbet?
What will happen to the value of F if the treatment effect stays the same but the random error increases?
Three groups of college students, 20 in each group, are given a list of eight nonsense syllables and required to learn the order in which the syllables appeared, by calling out the second syllable on
Students in an experimental psychology lab time how long it takes rats to run a maze. Ten students run the same 20 rats. Here is the average running time (to the nearest second) for each rat:a.
Indicate the first letter (N, O, I, R) of the highest possible scale for each of the following measures, where N is the lowest and R is the highest: Measure a. Hair length b. Species of tree c.
Indicate the first letter (N, O, I, R) of the highest possible scale for each of the following measures, where N is the lowest and R is the highest: Measure a. Feet of snow b. Brands of carbonated
Round the following numbers to two decimal places:a. 26.412 ____________b. 62.745 ____________c. 36.846 ____________
Round the following numbers to two decimal places:a. 95.555 ____________b. 0.023 ____________c. 48.950 ____________
Rearrange the equation to solve for the indicated unknown.a. 64/4 + b = 30 Solve for b: _____________________________b. 0.30c = 20 Solve for c: _____________________________c. Y = bX + a Solve for a:
Rearrange the equation to solve for the indicated unknown.a. b + 20 = 0.5 Solve for b: _____________________________b. F = 1.8c + 32 Solve for c: _____________________________c. 50 = 60/a Solve for
Rearrange the equation to solve for the indicated unknown.a. b + 24/8 = 3 Solve for b: _____________________________b. T = 12c − 4 Solve for c: _____________________________c. 12 = 3a Solve for a:
Forty college juniors were surveyed regarding the number of dates they had during the previous 30 days. Here are the data. Create a table, in descending score order, showing frequency and cumulative
A college instructor logs attendance throughout the semester for a class of 32 students that meets on M-W-F. Here is the number of classes each student missed during the semester. Create a table, in
The following 36 scores are the distances (to the nearest foot) that middle school boys threw a discus in a recent cross-country meet:69, 108, 70, 59, 86, 67, 54, 82, 9556, 74, 66, 74, 86, 82, 52,
In Table 3.6, what exact score falls at the 25th percentile rank? Use the appropriate formula. Table 3.6 Cumulative Relative Frequency for Statistics Test
Select a score from Table 3.6. Using the appropriate formula, determine that score’s percentile rank. Table 3.6 Cumulative Relative Frequency for Statistics Test
Thirty freshmen living on campus were asked how many times they skipped breakfast during the previous month. A check of their meal card swipes reveals the following number of skips:2, 4, 0, 7, 5, 8,
For the following 28 scores on a 40-point test,a. Construct a bar graph using 4-point score intervals andb. Draw a frequency curve using 4-point score intervals.
Select a score from Table 3.6. Using the appropriate formula, determine that score’s percentile rank. Table 3.6 Cumulative Relative Frequency for Statistics Test
One hundred and thirty-six breast cancer survivors participate in a community walk to raise money for fighting the disease. The number of women who walked various numbers of miles is listed below:a.
For the following political party registrations in a voting district,Republican = 5,924,Democrat = 3,622,Conservative = 840, andLiberal = 614,a. Construct a bar diagram andb. Construct a pie graph
Fifty clients of an outpatient mental clinic take an anxiety inventory. Scores range from 1 to 10. Here are the scores.a. Counting up from the bottom of the table, what is the ballpark median anxiety
For the following carbonated soft drink preferences of 100 college students,cola = 52,lemon-lime = 16,ginger ale = 4,orange = 10, androot beer = 18,a. Construct a bar diagram andb. Construct a pie
A behavior therapist is about to begin working with an ADHD (attention-deficit/ hyperactivity disorder) child in a classroom setting to reduce the number of times he gets out of his seat, talks out
Here is the same set of statistics test scores we worked with in Modules 3, 4, and 5.Find the (a) Range, (b) Variance, and (c) Standard deviation of the statistics test scores. Show

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