Question

Sample, Population, Statistic, and Range of Values.

For each study below, identify the sample used, the

population from which it was selected, the sample statistic(s), and the values of the confidence interval

likely to contain the true value of the population parameter(s).

1) “As many Americans prepare to celebrate Christmas, 72%say religion is important in their lives….

Although these findings, from a Dec. 3-12 Gallup poll, show that religion is still very important to a slim

majority, they provide further evidence of the long-term decline in the importance of religion in

Americans' lives…. Results for this Gallup poll are based on telephone interviews … with a random

sample of 1,025 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia. For

results based on the total sample of national adults, the margin of sampling error is ±4 percentage

points at the 95%confidence level.”

2) “More Texas voters oppose building a border wall with Mexico than support the idea, a new poll

released Thursday shows…. On the border wall, 53 percent opposed the idea….” “Quinnipiac University

surveyed 1,029 Texas voters with a margin of error of +/- 3.6 percentage points…..”

3) “‘Tis the season of anxiety for more than a third of U.S. adults who say the holidays stress them out,

according to the latest poll from the PBS NewsHour, NPR and Marist. Still, 58 percent of Americans say

the holidays are more fun than stressful…. The PBS NewsHour, NPR and Marist conducted a survey

Nov. 28-Dec. 4 that polled 1,075 U.S. adults with a margin of error of 3.7 percentage points.”

Answer 1

1)

Population: All adults of U.S.

Sample: 1025 adults selected

The 95% confidence interval is

2)

Population: All Texas voters

Sample: 1029 selected Texas voters

The confidence interval is

3)

Population: All adults of U.S.

Sample: 1075 adults selected

The confidence interval is

± ME-0.58 ± 0.037 = (0.543. 0.617)