Exam 3 ch 12, 14-16

Exam 3 Instructions: The exam is open book and open notes. It is not open internet or friend/acquaintance/enemy, though, so make sure you don’t talk to anyone about the content of the exam until you are both finished. You can use any of the resources/keys/lectures Dr. Woestehoff posted on Moodle, though. The t and F distribution tables are on Moodle and in the back of your textbook in the appendices. You can submit your exam on Moodle by uploading a Word document or a PDF. Make sure to label each question. For example, you could write “1. Z” for question 1, if you chose response letter “z”. Multiple choice. 1. The percentage of variance accounted for by the treatment effect is usually known as _____ in published reports of ANOVA results. a. µ 2 b. η 2 c. σ 2 d. α 2 e. 2. What is the purpose for post hoc tests? a. to determine whether or not a Type I error was committed b. to determine how much difference exists between the treatments c. to determine which treatments are significantly different d. to determine whether or not the sample is normally distributed 3. In an analysis of variance, what is a factor ? a. a dependent variable b. an independent variable c. a treatment mean d. a treatment total e. 4. A one-way analysis of variance is used to evaluate the mean differences for a research study comparing FOUR treatments with a separate sample of n = 8 in each treatment. If the data produce an F-ratio of F = 5.50, then which statistical decision is correct? (hint: you’ll need to calculate df and identify the F-criticals). a. Reject the null hypothesis with α = .05 but not with α = .01. b. Reject the null hypothesis with either α = .05 or α = .01. c. Fail to reject the null hypothesis with either α = .05 or α = .01. d. There is not enough information to make a statistical decision.

5. Dr. Fuzzy wants to know whether cat people or dog people have better eyesight. She gets two groups of people together. One group likes dogs and the other group likes cats. Then, she gives everyone an eye test. What statistical test would be most appropriate to use? a. Independent-samples t test b. Related-samples t test c. Analysis of Variance (ANOVA) d. z-score for sample mean 6. Sir Mix-A-Lot wants to know whether listening to Mozart makes people happier. He gathers one group of people and gives them a questionnaire about their happiness level. Then he asks everyone to listen to some Mozart. Afterwards, everyone answers the happiness questionnaire again. Which statistical test is best to use? a. Independent-samples t test b. Related-samples t test c. Analysis of Variance (ANOVA) d. z-score for sample mean 7. What would the scatterplot show for data that produce a correlation of +0.88? a. points clustered close to a line that slopes up to the right b. points clustered close to a line that slopes down to the right c. points widely scattered around a line that slopes up to the right d. points widely scattered around a line that slopes down to the right 8. Which correlation value shows the greatest strength or consistency of relationship? a. –0.90 b. +0.74 c. +0.85 d. –0.33 9. The results from a research study indicate that adolescents who watch more violent content on television also tend to engage in more violent behavior than their peers. The correlation between amount of TV violent content and amount of violent behavior is an example of a ____. a. positive correlation b. negative correlation c. correlation near zero d. correlation near one 10. A researcher obtains a Pearson correlation of r = 0.43. t = 2.02 and df = 18. For a two- tailed test, which of the following accurately describes the significance of the correlation? a. The correlation is significant with α = .05 but not with α = .01. b. The correlation is significant with either α = .05 or α = .01. c. The correlation is not significant with either α = .05 or α = .01. d. The correlation is equal to zero. e.

Here is the ANOVA summary table: Source SS df MS Between 9.6905 3 3.2302 F (3, 10) = 1.56 Within 20.6667 10 2.0667 Total 30.3571 13 -- 16. Make a decision regarding the null hypothesis and state whether hobbies affects exam scores (you’ll need to find F-critical first). a. F critical = 3.71 b. F = 1.56 c. df btw = 3 d. df within =10 e. F is < than F critical withα = .05 f. p> .05 g. A one-way ANOVA revealed that hobbies did not affect exams scores. 17. Would you conduct post-hoc tests on these data? Why or why not? a. A post-hoc test is used when you reject the H 0 or there is 3+ treatment, k ≥ 3 . In our case, a post-hoc tests needs to be conducted. The following questions corresponds to the scenario below. You are interested in the relationships between the number of hours per day students work (“work”) and the number of hours per day students spend on classwork (“classwork”). You collect data from 6 individuals. You find a correlation of r = -0.92, a t of -4.83, and df of 4. 18. Make a decision regarding the null hypothesis, assuming that α = .05 with a two-tailed test. Justify your decision. a. hours per day on student’s work = hours per day on classwork i. There is no relationship between student’s work and classwork. b. hours per day on student’s work ≠ hours per day on classwork. i. There is a relationship between student’s work and classwork. 19. Provide an interpretation of the results. a. The number of hours per day students work and the number of hours per day students spend on classwork has no relationship with each other, r= -0.92, n=6, p>0.05. 20. You decide to calculate a linear regression and find b = -1.18. Provide an interpretation for the b value. Assume “work” is the predictor. a. With b being -1.18, a negative number, the slope will be negative which will result in the line to be falling. Moving on…

Explain how you would research the following hypotheses/research questions (in other words, the methodology – how would you collect the data?).  Make sure to specify what the independent and dependent variables, if appropriate (not all research studies have independent and dependent variables). o independent variables = Work and classwork o dependent variable = hours spent  Specify what type of design you would use (between-participants, within-participants, or correlational). o Correlational  Indicate which statistical test you should use, and why you chose that test. o I would use a Pearson correlation test because we are comparing two independent variables. We want to know if there’s any relationship between the two variables. Choose THREE (3) of the following 6 questions to answer. Make sure to label each question in your answers with the correct number. 21. Emperor Palpatine wants to see whether there is a relationship between the number of death stars in a galaxy (0-5) and the number of planets that exploded (0-3). 22. Darth Vader wants to compare the number of rebel scum on the planet Hoth to the number of rebel scum in the entire universe. Darth Vader doesn’t know the exact number in the universe. a. Independent measure t-test 23. Marty McFly wants to examine the influence of song type (Toxic vs. Bad Blood vs. Uptown Funk) on how many people dance at prom. a. ANOVA 24. Princess Leia wants to see whether stormtroopers or Rebel Alliance soldiers hit more targets. 25. Jack Skellington wants to see whether children think zombies or vampires are scarier. a. Repeated measure t-test 26. Elsa wants to see whether there is a relationship between the temperature outside and the number of people frozen. a. Pearson Correlation Additional questions. 27. Jar Jar Binks conducted a correlation between the number of flowers in a field and the number of planets in the solar system. He had a p -value of .043, n of 452, and a correlation coefficient of .89. “We need to grow more flowers,” Jar Jar says, “because the number of flowers causes a greater number of planets!” Are his conclusions justified? Why or why not? a. There is a relationship between the numbers of flowers in a field and the number of planets in our solar system. When conducting the experiment, I found that p<.05 because r= .043 is greater that alpha at 0.05. So, Jar Jar is correct. 28. Carol and Daryl created a zombie survival training course and conduct an experiment. They randomly assign half of their participants to the zombie survival training course and