Quiz 1

1.   Problem 1. The Gallup Organization conducted a survey of 2,718 adults living in the United States and asked, “If you
had one thousand dollars to spend, do you think investing it in the stock market would be a good or bad idea?” Of
the 2,718 adults, 42% said it would be a bad idea. The Gallup Organization reported that 42% of all adults living in
the United States thought it was a bad idea to invest $1000 in the stock market with a 6% margin of error with 98%
confidence.
(a) (1 point) What is the research objective?
(b) (1 point) What is the population?
(c) (1 point) What is the sample?
(d) (1 point) List the descriptive statistics.
(e) (1 point) What can be inferred from this survey?

2.  Problem 2. Are young couples who marry or live together more likely to gain weight than those who stay single?
Researchers followed 8000 men and women for seven years. At the start of the study, none of the participants were
married or living with a romantic partner. The researchers found that women who married or lived with a partner during
the study gained, on average, 9 pounds more than single women. And men who married or lived with a partner gained,
on average, 6 pounds more than single men.
(a) (2 points) Is this an observational study or experiment? Why?
(b) (2 points) What are the explanatory and response variables? Are the variables quantitative or categorical?
(c) (2 points) Can we conclude that getting married or living with a partner causes weight gain? Explain.
Problem 3. (1 point each) Identify the sampling method used.
(a) A college administrator divides the student population into four classes: freshman, sophomore, junior, and senior.
She takes a simple random sample from each class and surveys the participants about student services on campus.
(b) A farmer divides his orchard into 50 subsections, randomly selects 4, and samples all the trees within the 4 subsections
to approximate the yield of his orchard.
(c) A radio station asks its listeners to call in their opinion regarding the use of U.S. forces in peacekeeping missions.