Activity 24-1: Birthdays of the Week
a. The observational units are the writers.
The variable is the day of the week on which the birthday falls.
b. The following bar graph displays the
Tests of Significance: Proportions
Activity 17-1: Kissing Couples
a. The parameter of interest in this study is ! = the population proportion of all kissing couples who turn
their heads to the right.
b. H0: ! = 5.
c. Ha: ! > .
Confidence Intervals: Means
Activity 19-1: M&M Consumption
a. The variable number of M&Ms selected is quantitative.
b. The numbers x = 50.15 and s = 30.31 are statistics.
c. The parameter in this study is ! = the average numbe
Tests of Significance: Means
Activity 20-1: Backpack Weights
a. The summary statistics show this sample data has a mean less than .10, which is what is conjectured
by the researchers.
b. The parameter of interest in this study
Comparing Two Proportions
Activity 21-1: Dolphin Therapy.
a. The research question that motivated this study was Is swimming with dolphins more therapeutic for
patients suffering from clinical depression than the natural progr
Comparing Two Means
Activity 22-1: Close Friends
a. This is an observational study because the researcher simply observed the gender of each subject.
He/she did not randomly assign gender to subjects.
b. Explanatory variable:
Activity 6-1: Feeling Rushed
a. The observational units in this study are the adult Americans that responded to the General Social
Survey. The sample size is 304 + 513 + 160 = 977.
b. The bar graph below displays
Confidence Intervals: Proportions
Activity 16-1: Generation M.
a. The observational units are the American youths ages 8-18.
b. The variable is whether each youth has a television in her or his bedroom, and it is categorical a
Data and Distributions
Activity 2-1: Penny Thoughts
a. This is a binary categorical variable.
b. Answers will vary by class. One example is 15/18, or 0.833 voted to retain the penny.
c. Answers will vary. One example is 3/18, o
Data and Variables
Activity 1-1: Cell Phone Calls
a. Answers will vary.
b. Answers will vary, but it is unlikely that every student will have made the same number of outgoing
c. The number of outgoing calls is a quantita