## Make a two-way table from Table 1A for gender and living situation.

Make a two-way table from Table 1A for gender and living situation. Put the labels Male and Female across the top and Dorm and Commuter on the side and then tally the data.

a. Report how many are in each cell.

b. Find the sums for each column and row and the grand total and put them into your table. The grand total is the total number of people and is put in the lower right corner.

c. What percentage of the females live in a dorm?

d. What percentage of the people living in a dorm are female?

e. What percentage of people live in a dorm?

f. If the distribution of females remained roughly the same and you had 70 females, how many of them would you expect to be living in the dorm?

## A survey was done of men’s and women’s hands to see if

A survey was done of men’s and women’s hands to see if the ring finger appeared longer than the index finger or not. Yes means the ring finger is longer, and No means the ring finger appears shorter or the same length as the index finger. The students in this survey were not told the theory that men are more likely to have a longer ring finger than women due to more testosterone.

a. What percentage of the men said Yes?
b. What percentage of the women said Yes?
c. What percentage of the people who said Yes were men?
d. If a large group of 250 men had the same rate of responses as the men in this sample, how many men of the 250 would say yes?

## A data set on Shark Attacks Worldwide posted on StatCrunch records data

A data set on Shark Attacks Worldwide posted on StatCrunch records data on all shark attacks in recorded history including attacks before 1800. Variables contained in the data include time of attack, date, location, activity the victim was engaged in when attacked, type of injuries sustained by the victim, whether or not the injury was fatal, and species of shark. Which of the following questions could not be answered using this data set? (Source: www.sharkattackfile.net)

a. In what month do most shark attacks occur?

b. Are shark attacks more likely to occur in warm temperature or cooler temperatures?

c. Attacks by which species of shark are more likely to result in a fatality?

d. What country has the most shark attacks per year?

## Make a two-way table from Table 1 for gender and hair color.

Make a two-way table from Table 1 for gender and hair color. Put the labels Male and Female across the top and Brown, Black, Blonde, and Red and then tally the data.
a. Report how many are in each cell.

b. Find the sums of each row and column and the grand total and put them into your table.

c. What percentage of the females have brown hair?

d. What percentage of the people who have brown hair are female?

e. What percentage of the people have brown hair?

f. If the distribution of hair color of females remained roughly the same and you had 60 females, how many of them would have brown hair?

## Researchers wanted to assess whether a theory-based, community health worker–delivered intervention

Researchers wanted to assess whether a theory-based, community health worker–delivered intervention for household smokers will lead to reduced secondhand smoke exposure to children in Chinese families. Smoking parents or caregivers who had a child aged 5 years or younger at home were randomly assigned to the intervention group that received information on smoking hygiene and the effects of secondhand smoke exposure delivered by community health workers or to the comparison group who received no additional information regarding secondhand smoke. At a 6-month follow-up, researchers assessed whether or not families had adopted any smoking restrictions at home. The results are shown in the following table. (Abdullah et al., “Secondhand smoke exposure reduction intervention in Chinese households of young children: A randomized controlled trial,” Academic Pediatrics, vol. 15(November–December 2015): 588–598, . acap.2015.06.008)

a. What percentage of those receiving the intervention adopted smoking restrictions at home?

b. What percentage of those in the control group adopted smoking restrictions at home?

c. Based on this data, do you think the intervention may have been effective in promoting the adoption of smoking restrictions in the home?

## A study was conducted to see whether participants would ignore a sign

A study was conducted to see whether participants would ignore a sign that said, “Elevator may stick between floors. Use the stairs.” The study was done at a university dorm on the ground floor of a three-level building. Those who used the stairs were said to be compliant, and those who used the elevator were said to be noncompliant. There were three possible situations, two of which involved confederates. A confederate is a person who is secretly working with the experimenter. In the first situation, there was no confederate. In the second situation, there was a compliant confederate (one who used the stairs), and in the third situation, there was a noncompliant confederate (one who used the elevator). The subjects tended to imitate the confederates. What more do you need to know about the study to determine whether the presence or absence of a confederate causes a change in the compliance of subjects? (Wogalter et al. [1987], reported in Shaffer and Merrens, Research Stories in Introductory Psychology [Boston: Allyn and Bacon, 2001])

## An article in the journal BMC Medicine reported on a study designed

An article in the journal BMC Medicine reported on a study designed to study the effect of diet on depression. Subjects suffering from moderate to severe depression were randomly assigned to one of two groups: a diet intervention group and a social support control group. The 33 subjects in the diet intervention group received counseling and support to adhere to a “ModiMedDiet,” based primarily on a Mediterranean diet. The 34 subjects in the social support group participated in a “befriending” protocol, where trained personnel engaged in conversation and activities with participants. At the end of a 12-week period, 11 of the diet intervention group achieved remission from depression compared to 3 of the control group.

a. Find and compare the sample percentage of remission for each group.
c. Can we conclude that the diet caused a remission in depression? Why or why not?

## An article in the Journal of the Academy of Nutrition and Dietetics

An article in the Journal of the Academy of Nutrition and Dietetics reported on a study of diet in subjects with moderate to severe acne. Read the excerpts from the abstract and answer the questions that follow. (Burris et al., “Differences in dietary glycemic load and hormones in New York City adults with no or moderate/severe acne,” Journal of the Academy of Nutrition and Dietetics, vol. 117 [September 2017]: 1375–1383) Methods: Sixty-four participants (no acne, n = 32; moderate/severe acne, n = 32) were included in this study. Participants completed a 5-day food record, had blood drawn and completed a questionnaire to evaluate food-aggravated acne beliefs and acne-specific quality of life. Results: Participants with moderate/severe acne consumed greater total carbohydrate compared to participants without acne. Participants with moderate/severe acne had greater insulin compared to participants Without acne. Although there were no differences between groups, 61% of participants reported food-influenced acne.

a. Was this a controlled experiment or an observational study? Explain how you know.

b. Assuming the study was properly conducted, can we conclude that higher consumption of carbohydrates causes more severe acne? Explain.

## In a 2017 study designed to investigate the effects of exercise on

In a 2017 study designed to investigate the effects of exercise on second language learning, 40 subjects were randomly assigned to one of two conditions: an experimental group that engaged in simultaneous physical activity while learning vocabulary in a second language and a control group that learned the vocabulary in a static learning environment. Researchers found that learning second-language vocabulary while engaged in physical activity led to higher performance than learning in a static environment. Liu et al., “It takes biking to learn: Physical activity improves learning a second language,” PLoS One, May 18, 2017, .  pone.0177624

a. What features of a well-designed controlled experiment does this study have? Which features are missing?

b. Assuming that the study was properly conducted, can we conclude that the physical activity while learning caused the higher performance in learning second-language vocabulary? Explain.

## A study reported by Griffin et al. compared the rate of pneumonia

A study reported by Griffin et al. compared the rate of pneumonia between 1997 and 1999 before pneumonia vaccine (PCV7) was introduced and between 2007 and 2009 after pneumonia vaccine was introduced. Read the excerpts from the abstract, and answer the question that follows it. (Source: Griffin et al., “U.S. hospitalizations for pneumonia after a decade of pneumococcal vaccination,” New England Journal of Medicine, vol. 369 [July 11, 201]: 155–163) We estimated annual rates of hospitalization for pneumonia from any cause using the Nationwide Inpatient Sample database. . . . Average annual rates of pneumonia-related hospitalizations from 1997 through 1999 (before the introduction of PCV7) and from 2007 through 009 (well after its introduction) were used to estimate annual declines in hospitalizations due to pneumonia. The annual rate of hospitalization for pneumonia among children younger than 2 years of age declined by 551.1 per 100,000 children . . . which translates to 47,000 fewer hospitalizations annually than expected on the basis of the rates before PCV7 was introduced. Results for other age groups were similar. Does this show that pneumonia vaccine caused the decrease in pneumonia that occurred? Explain.