#1 Find the margin of error for the given values of c, , and n.

c=0.90,

=3.1,

n=100

E= (Round to three decimal places as needed.)

#2 Construct the confidence interval for the population mean

.

c=0.98,

x=16.9,

=7.0,

and

n=60

A 98% confidence interval for is

(Round to one decimal place as needed.)

#3 Find the minimum sample size n needed to estimate for the given values of c, , and E.

c=0.95,

=6.5,

and

E=1

Assume that a preliminary sample has at least 30 members.

n=

(Round up to the nearest whole number.)

#4 Use the confidence interval to find the estimated margin of error. Then find the sample mean.A biologist reports a confidence interval of (1.9,2.7) when estimating the mean height (in centimeters) of a sample of seedlings.

#5 A publisher wants to estimate the mean length of time (in minutes) all adults spend reading newspapers. To determine this estimate, the publisher takes a random sample of 15 people and obtains the results below. From past studies, the publisher assumes is 2.4 minutes and that the population of times is normally distributed.

11 11 7 6 6 12 12 10 6 11 11 9 12 7 7

Construct the 90% and 99% confidence intervals for the population mean. Which interval is wider? If convenient, use technology to construct the confidence intervals.

#6 You are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. If convenient, use technology to construct the confidence intervals.A random sample of 55 home theater systems has a mean price of $119.00. Assume the population standard deviation is $15.30.

(a)The 90% confidence interval is

(b)The 95% confidence interval is

(c) Interpret the results

#7 Find the minimum sample size n needed to estimate for the given values of c, , and E.

c=0.98,

=5.4,

and E=1

Assume that a preliminary sample has at least 30 members.

n=

(Round up to the nearest whole number.)

#8 Determine the minimum sample size required when you want to be 95% confident that the sample mean is within one unit of the population mean and =14.3. Assume the population is normally distributed.

A 95% confidence level requires a sample size of

(Round up to the nearest whole number as needed.)