In a survey of 1000 people, 60% said that they have never hesitated to give a ha

Question

In a survey of 1000 people, 60% said that they have never hesitated to give a handshake because they had fear of germs. The survey results were reported in USA Today, and the survey is conducted by Wakefield Research for Purell, a supplier of had sanitizer products. 2. Construct a 95% confidence interval estimate of the proportion of people in the population who have never hesitated to give a handshake because of a fear of germs a) 6 pts.) c) Is there anything about the survey that might make the results questionable? Explain 3 pts.) If an independent pollster wanted to conduct another survey to confirm or refute the results, how many people must be surveyed? Assume we want 90% confidence that the sample percentage is within 2 percentage points of the true population proportion. c) 6 pts.)

Explanation / Answer

2)a) At 95% Confidence interval the critical value is 1.96

The Confidence interval is

P +/- z0.025 * sqrt (P * (1 - P)/n )

= 0.6 +/- 1.96 * sqrt(0.6 * 0.4 /1000)

= 0.6 +/- 0.03

= 0.57, 0.63

C) At 90% Confidence interval the critical value is 1.645

Margin of error = 0.02

Or, z0.05 * sqrt (P * (1 - P )/n) = 0.02

Or, 1.645 * sqrt(0.6 * 0.4/n) = 0.02

Or, sqrt(n) = 1.645 * sqrt(0.6 * 0.4)/0.02

Or, sqrt(n) = 40.294

Or, n = 1624

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.