1. Intro to Stats and Collecting Data

Use the Venn diagram to identify the population and the sample.

"Identify the population and the sample. Describe the sample data set.

To gather information about starting salaries at companies listed in the Standard & Poor’s 500, a researcher contacts 74 of the 500 companies."

Green Tea You wonder whether green tea lowers cholesterol.

Explain how to use randomization in this experiment. How does randomization neutralize those variables that are not controlled?

What are the advantages of having a presurvey when constructing a questionnaire that has closed questions?

Discuss a possible advantage of offering rewards or incentives to increase response rates. Are there any disadvantages?

Order of the Questions Consider the following two questions: Currently, social media companies, such as Facebook, profit by selling user data. Do you believe the government should regulate the ability of social media companies to sell user data?

Do you think the order in which the questions are asked will affect the survey results? If so, what can the pollster do to alleviate this response bias?

Identify the population and the sample. Describe the sample data set.

Eighty-three doctors working in the St. Louis area were surveyed concerning their opinions on health care reform.

A software development company created a new app for fitness, and they want to determine if using the app can lead to weight loss and increased strength in customers. Should they run an observational study or experiment?

"[DATA] Putting It Together: Paternal Smoking It is well-documented that active maternal smoking during pregnancy is associated with lower-birth-weight babies. Researchers wanted to determine if there is a relationship between paternal smoking habits and birth weight. The researchers administered a questionnaire to each parent of newborn infants. One question asked whether the individual smoked regularly. Because the survey was administered within 15 days of birth, it was assumed that any regular smokers were also regular smokers during pregnancy. Birth weights for the babies (in grams) of nonsmoking mothers were obtained and divided into two groups, nonsmoking fathers and smoking fathers. The given data are representative of the data collected by the researchers. The researchers concluded that the birth weight of babies whose father smoked was less than the birth weight of babies whose father did not smoke.

a. Is this an observational study or a designed experiment? Why?"

A company wants to test the effectiveness of a new acne cream. The company recruits 500 girls ages 13 to 17 who have acne. The subjects are randomly assigned into two groups. One group is given the acne cream and the other is given a placebo that looks exactly like the acne cream. Both groups apply the cream daily for two months. Facial photos are taken at the beginning and end of the treatment to compare results.

c. How could this experiment be designed to be double-blind?

"Identify the population and the sample. Describe the sample data set.

A survey of 1500 U.S. adults found that 59% have never had a vaccine reaction. (Source: SingleCare)"

Determine whether the study is an observational study or an experiment. Explain.

Researchers conduct a study to determine whether a medication based on fish oil known as omega-3 carboxylic acids is effective in reducing the risk of cardiac events in people already at risk. In the study, 13,078 patients are randomly chosen to receive either omega-3 carboxylic acids or a placebo of corn oil daily. Researchers compare the number of cardiac events of the two groups over similar follow-up periods of time. (Source: American Heart Association)

Use the Venn diagram to identify the population and the sample.

What is the difference between a census and a sampling?

Determine whether the study is an observational study or an experiment. Explain.

Researchers conduct a study to determine whether cataract surgery patients experience different comfort levels during their first and second surgeries. Researchers based their results on a verbal questionnaire. (Source: Medicine)