Rasmussen College - STA3215 - Module 2 Homework

1.

The local news provided poll results from 2000 adults who interview job applicants. The results showd that 35% of the adults said their biggest issue with interviewers is them not knowing company history.

The margin of error was given as +/- 4 percentage points. Answer the following questions:

a. What important piece of information was omitted from the statement above?

b. What is meant by the statement that "the margin of error is +/- 4 percentage points"?

c. What are the values of

d. If the confidence level is 95%, what is the value of

e. Which confidence interval is wider: the 95% confidence interval or the 80% confidence interval. Why?

2.

In a poll of 555 randomly selected students, 40% stated that they enjoyed statistics. Answer the following questions:

a. Identify the number of students who say that they enjoy statistics? Round to the nearest whole student if necessary.

3.

The following information provided below shows the output from the results of performing a confidence interval for a population mean. Answer the following questions:

Confidence Interval (233.4, 256.65)

245.025

36.35754604

n 40

a. Identify the best point estimate of

b. Find the degrees of freedom.

c. Find the critical valuethat corresponds to n = 40.

d. Find the margin of error E.

e. A statement that correctly interprets the confidence interval.

b. Construct a 95% confidence interval estimate of the percentage of all students who say that they enjoy statsitics.

4.

The cholesterol levels of 40 women were sampled and a 95% confidence interval estimate was obtained below. The units of measurement for the interval below are

917.562<< 2254.129

a. Identify the confidence interval. Include the appropriate units of measure.

b. a statement that correctly interprets the confidence intervale estimate of .

c. Can we safely conclude that majority of students enjoy statistics? Explain.

5.

You want to estimate the mean amount of time college students spend on the Internet each month. How many college students must you survey to be 95% confident that your sample mean

is within 15 minutes of the population mean? Assume that the standard deviation of the population of monthly time spent on the Internet is 210 minutes.