INTRODUCTORY STATISTICS (LOOSELEAF)
3rd Edition
ISBN: 9780135163146
Author: Gould
Publisher: PEARSON
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Chapter 12, Problem 23SE
Dietary Improvement and Depression In a 2017 study, researchers investigated the effect of dietary improvement on adults with moderate to severe depression (Jacka et al. 2017). Subjects were randomly assigned to a treatment group consisting of seven individual nutritional consulting sessions with a clinical dietician or a control condition consisting of a social support protocol with the same visit schedule and length as the treatment group. There were 33 subjects in the treatment group and 34 subjects in the control group. Remission from depression symptoms was achieved by 10 subjects in the treatment group and 2 subjects in the control group.
a. Was this an observational study or a controlled experiment? Explain.
b. Find the percentage in each group that achieved remission from depression symptoms.
c. Researchers performed a test to determine if there was significant difference in outcomes between the treatment and control groups. The
i. Researchers have shown that dietary improvement may be an effective treatment strategy for patients with moderate to severe depression.
ii. Researchers have not shown that dietary improvement may be an effective treatment strategy for patients with moderate to severe depression.
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very time you conduct a hypothesis test, there are four possible outcomes of your decision to reject or not reject the null hypothesis: (1) You don’t reject the null hypothesis when it is true, (2) you reject the null hypothesis when it is true, (3) you don’t reject the null hypothesis when it is false, and (4) you reject the null hypothesis when it is false.
Consider the following analogy: You are an airport security screener. For every passenger who passes through your security checkpoint, you must decide whether to select the passenger for further screening based on your assessment of whether he or she is carrying a weapon. Suppose your null hypothesis is that the passenger has a weapon. As in hypothesis testing, there are four possible outcomes of your decision: (1) You select the passenger for further inspection when the passenger has a weapon, (2) you allow the passenger to board her flight when the passenger has a weapon, (3) you select the passenger for further inspection when…
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Stress at work: In a poll conducted by the General Social Survey, 81% of respondents said that their jobs were sometimes or always stressful. Two hundred
workers are chosen at random. Use the TI-84 Plus calculator as needed. Round your answer to at least four decimal places.
(a) Approximate the probability that 155 or fewer workers find their jobs stressful.
(b) Approximate the probability that more than 145 workers find their jobs stressful.
(c) Approximate the probability that the number of workers who find their jobs stressful is between 154 and 172 inclusive.
Part 1 of 3
The probability that 155 or fewer workers find their jobs stressful is 0.1207
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bility that more than 145 workers find their jobs…
A case-control (or retrospective) study was conducted to investigate a relationship between the colors of helmets worn by motorcycle drivers and whether they are injured or killed in a crash. Results are given in the accompanying table. Using a 0.01
significance level, test the claim that injuries are independent of helmet color.
Color of Helmet
Black
White
Yellow
Red
Blue
Controls (not injured)
499
373
32
159
79
Cases (injured
221
108
8
66
38
or killed)
Click here to view the chi-square distribution table.
Chi-square distribution table
Area to the Right of the Critical Value
Degrees of
Freedom
0.995
0.99
0.975
0.95
0.90
0.10
0.05
0.025
0.01
0.005
C. Ho: Injuries and neimet color are dependent
H₁: Injuries and helmet color are independent
D. Ho: Whether a crash occurs and helmet color are dependent
1
0.001
0.004
0.016
2.706
3.841
5.024
6.635
7.879
2
0.010
0.020
0.051
0.103
0.211
4.605
5.991
7.378
9.210
10.597
3
0.072
0.115
0.216
0.352
0.584
6.251
7.815
9.348
11.345
12.838
4
0.207
0.297…
Chapter 12 Solutions
INTRODUCTORY STATISTICS (LOOSELEAF)
Ch. 12 - Dairy Products and Muscle The following two...Ch. 12 - Coffee and Depression The following two headlines...Ch. 12 - Marijuana Use and Bone Density In a 2017 study...Ch. 12 - Prob. 4SECh. 12 - Prob. 5SECh. 12 - Prob. 6SECh. 12 - Prob. 7SECh. 12 - Smoking Cessation In a 2018 study reported in The...Ch. 12 - Prob. 9SECh. 12 - Prob. 10SE
Ch. 12 - Prob. 11SECh. 12 - Sugary Drinks and Brain Health An April 2017...Ch. 12 - Expression of Feelings A 2017 Pew poll asked a...Ch. 12 - Prob. 14SECh. 12 - Prob. 15SECh. 12 - SAT Prep and Power Suppose an SAT tutoring company...Ch. 12 - Brain Games (Example 2) Researchers are interested...Ch. 12 - A Smile a Day Smiling is a sign of a good mood,...Ch. 12 - Speed Skating Suits (Example 3) Speed skating is a...Ch. 12 - Flu Vaccines and Age Suppose you want to compare...Ch. 12 - Preventing Heart Attacks with Aspirin Suppose that...Ch. 12 - Prob. 22SECh. 12 - Dietary Improvement and Depression In a 2017...Ch. 12 - Prob. 24SECh. 12 - Reading Colored Paper (Example 4) Some people...Ch. 12 - Prob. 26SECh. 12 - Prob. 27SECh. 12 - Prob. 28SECh. 12 - Prob. 29SECh. 12 - Library Audio Books Suppose a college is deciding...Ch. 12 - Prob. 31SECh. 12 - Prob. 32SECh. 12 - Prob. 33SECh. 12 - Prob. 34SECh. 12 - Prob. 35SECh. 12 - Prob. 36SECh. 12 - Prob. 37SECh. 12 - Prob. 38SECh. 12 - Prob. 39SECh. 12 - Prob. 40SECh. 12 - Prob. 41SECh. 12 - Prob. 42SECh. 12 - Prob. 43SECh. 12 - Prob. 44SECh. 12 - Yoga Study Design Refer to exercise 12.43. How...Ch. 12 - Fish Consumption Study Design Refer to exercise...Ch. 12 - Prob. 47SECh. 12 - Prob. 48SECh. 12 - Alumni Donations The alumni office wishes to...Ch. 12 - Prob. 50SECh. 12 - Prob. 51SECh. 12 - Prob. 52SECh. 12 - For exercises 12.51-12.53, evaluate the study...Ch. 12 - Prob. 54SECh. 12 - Anesthesia Care and Adverse Postoperative Outcomes...Ch. 12 - Prob. 56SECh. 12 - Prob. 57SECh. 12 - Prob. 58SE
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