The paper “Mood Food: Chocolate and Depressive Symptoms in a Cross-Sectional Analysis” (Archives of Internal Medicine [2010]: 699–703) describes a study that investigated the relationship between depression and chocolate consumption. Participants in the study were 931 adults who were not currently taking medication for depression. These participants were screened for depression using a widely used screening test. The participants were then divided into two samples based on the score on the screening test. One sample consisted of people who screened positive for depression, and the other sample consisted of people who did not screen positive for depression. Each of the study participants also completed a food frequency survey.
The researchers believed that the two samples were representative of the two populations of interest—adults who would screen positive for depression and adults who would not screen positive. The paper reported that the
Estimate the difference in the mean number of servings of chocolate per month in the population of people who would screen positive for depression and the mean number of chocolate servings per month in the population of people who would not screen positive for depression. Use a confidence level of 90% and be sure to interpret the interval in context.
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Chapter 11 Solutions
Introduction to Statistics and Data Analysis
- 3. A researcher was interested in the effects of a drug on depression. Subjects were randomly assigned to one of the three groups. Subjects in the control group received a placebo and the subjects in the two treatment groups received either a 0.2 mg or a 0.4 mg dosage of the drug. After several weeks of drug (or placebo) treatment, the researcher measured the subjects' level of depression (a low score indicating greater depression) The following data were obtained. Placebo 0.2 mg 0.4 mg 12 11 12 10 9. 14 11 11 17 13 13 16 15 7 16 12 Mean of X = 10 14 12 S^2 = 5.6 8.4 Using 5% of significance, test the hypothesis that the three groups differ in their effectiveness.arrow_forwardThe National Highway traffic Safety Administration requires each U.S. state to carry out an observational study to assess the level of seat belt use in the state. One report summarized data from a study done in a certain state. The proportions in the accompanying table are based on observations of over 25,000 drivers and passengers. Uses Seatbelt Does Not Use Seat Belt Male 0.425 0.075 Female 0.452 0.048 Assume that these proportions are representative of adults in this state and that an adult from this state is selected at random. (a) What is the probability that the selected adult uses a seat belt? (b) What is the probability that the selected adult uses a seat belt given that the individual selected is male?arrow_forwardThanh Nguy.. Empathy: The Interpersonal Reactivity Index is a survey designed to assess four different types of empathy. One type of empathy, called Empathetic Concern, measures the tendency to feel sympathy and compassion for people who are less fortunate. The index ranges from 0 (less empathetic) to 28 (more empathetic). The following data, representing random samples of 12 males and 12 females, are consistent with results reported in psychological studies. Boxplots show that it is reasonable to assume that the populations are approximately normal. Can you conclude that the mean empathy score for men is less than the mean empathy score for women? Let u, denote the mean empathy score for men. Use the a = 0.01 level and the P-value method with the TI-84 Plus calculator. Males 20 12 16 13 26 21 23 15 18 25 15 Females 22 20 26 25 28 24 16 19 20 23 21 23 Send data to Excel Part 1 of 4 State the null and alternate hypotheses. i = ':°H i 'i:'H test. The hypothesis test is a two-tailed Part:…arrow_forward
- Researchers asked soda drinkers to view either the logo for their favorite soda or a graphic warning demonstrating the harmful effects of sugary beverages (e.g., tooth decay, obesity) and then measured their negative mood with a short survey. They found that those participants who saw the warnings reported significantly greater negative moods than those who saw the logos. Which statistical test should be used?arrow_forwardA forensic psychologist is interested in assessing the prevalence of major depressive disorders among a sample of prison inmates. A random sample of inmates was selected and tested on the MDI (Major Depressive Inventory), a self-report instrument designed to measure levels of depression. Their scores were: 8, 10, 4, 11, 7, 10, 13, 4, 8, 7, 9, 3, 15, 10, 10, 10, & 13. a.) Use descriptive statistics including sample size, skewness, kurtosis, mean, median, mode, range, and standard deviation to describe this sample. Write your results in a paragraph similar to the Results section of a manuscript. b.) If the MDI has a µ = 10, is the depression of prison inmates significantly different than that of the general population? Test with an α = 0.05. c.) What type of error is possible based on the outcome? I need help learning these questions.arrow_forwardWhirling disease is a deadly disease that affects trout in Montana riversIn a follow-up to a 2006 study conducted by the Montana Department of FishWildlife and Parks (FWP)researchers sought to determine if the proportion of trout afflicted by whirling disease in the Gallatin river differs between rainbow trout and brown trout. To test this theory, researchers collected a representative sample of 527 rainbow trout and 459 brown trout. Of the 527 rainbow trout collected, 120 had developed whirling disease; of the 459 brown trout collected, 74 had developed whirling disease Calculate the relative risk of whirling disease for rainbow trout compared to brown trout in this sample.arrow_forward
- As part of a long-term study of individuals 65 years of age or older, sociologists and physicians at the Wentworth Medical Center in upstate New York investigated the relationship between geographic location and depression. A sample of 60 individuals, all in reasonably good health, was selected; 20 individuals were residents of Florida, 20 were residents of New York, and 20 were residents of North Carolina. Each of the individuals sampled was given a standardized test to measure depression. Higher test scores indicate higher levels of depression. A second part of the study considered the relationship between geographic location and depression for individuals 65 years of age or older who had a chronic health condition such as arthritis, hypertension, and/or heart ailment. A sample of 60 individuals with such conditions was identified. Again, 20 were residents of Florida, 20 were residents of New York, and 20 were residents of North Carolina. Prepare a managerial report that summarizes…arrow_forward“Are Women Really More Talkative Than Men?” is the title of an article that appeared in the journal Science. In the article, Mehl, Vazire, Ramirez-Esparza, Slatcher, & Pennebaker (2007) report the results of a study of 396 men and women. Each participant wore a microphone that recorded every word he or she uttered. The researchers counted the number of words uttered by men and women and compared them. The data below are fictional but they re-create the pattern that Mehl and colleagues observed: Men: 16,345 17,222 15,646 14,889 16,701 Women: 17,345 15,593 16,624 16,696 14,200 Conduct steps for hypothesis testing. Calculate the 95% confidence interval. (MX - MY)lower = -1481.575 (MX - MY)upper = 1343.575arrow_forward6.50 How's it going?: The American National Election Studies (ANES) collects data on voter attitudes and intentions as well as demographic information. In this question we will focus on two variables from the ANES dataset (ANES, 2012). region (levels: Northeast, North Central, South, and West) • whether the respondent feels things in this country are generally going in the right direction or things have pretty seriously gotten off on the wrong track To keep calculations simple we will work with a random sample of 500 respondents from the ANES dataset. The distribution of responses are as folows: Right Direction Wrong Track Total Northeast 29 54 83 North Central 44 77 121 South 62 131 193 West 36 67 103 Total 171 329 500 There are TW0 parts to this question. One is a Chi-Squared GOF and one is a Chi-Squared Test for Independence. Think about the differences between the two tests to determine which one to use on which part. a) Region: According to the 2010 Census, 18% of US residents…arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage LearningBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt