Statistics
posted by Katie on .
These are the only ones that I am having problems with. Please help..
8.You are given the sample mean and the sample standard deviation. Use this information to construct the 90% and the 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. If convenient, use the technology to construct the confidence intervals
A random sample of 35 home theater systems has a mean price of $142.00 and a standard is $19.80
Construct a 90% confidence for the population mean:
The 90% confidence interval is
Construct a 95% confidence for the population mean:
The 95% confidence interval is
(Round to two decimals places as needed for both answers)
9. You are given the sample mean and the sample standard deviation. Use this information to construct the 90% and the 95% confidence intervals for the population mean. Which interval is wider? If convenient, use the technology to construct the confidence intervals
A random sample of 34 gas grills has the mean price of $649.30 and a standard deviation of $58.70
Construct a 90% confidence for the population mean:
The 90% confidence interval is
Construct a 95% confidence for the population mean:
The 95% confidence interval is
(Round to two decimals places as needed for both answers)
10.You are given the sample mean and the sample standard deviation. Use this information to construct the 90% and the 95% confidence intervals for the population mean. Which interval is wider? If convenient, use the technology to construct the confidence intervals
A random sample of 39 eightounce servings of different juice drinks has a mean of 79.4 calories and a standard deviation of 40.7 calories.
Construct a 90% confidence for the population mean:
The 90% confidence interval is ______________
Construct a 95% confidence for the population mean:
The 95% confidence interval is ___________
16. In a survey of 646 males ages 18 – 64, 392 say they have gone to the dentist in the past year.
Construct 90% and 95% confidence intervals for the population proportions. Interpret the results and compare the widths of the confidence intervals. If convenient, use technology to construct the confidence intervals.
The 90% confidence interval for the population proportion p is (____,_____)
(Round the final answers to the nearest thousandth as needed. Round all intermediate vales to the nearest thousandth as needed)
The 95% confidence interval for the population proportion p is (____,_____)
Interpret your results of both confidence intervals.
A. With the given confidence, it can be said that the population proportion or males ages 1864 who say they have gone to the dentist in the past year is not between the endpoints of the given confidence interval.
B. With the given confidence, it can be said that the sample proportion or males ages 1864 who say they have gone to the dentist in the past year is between the endpoints of the given confidence interval.
C. With the given confidence, it can be said that the population proportion or males ages 1864 who say they have gone to the dentist in the past year is between the endpoints of the given confidence interval.
Which is wider?
The 90% confidence interval
The 95% confidence interval

We do not do your homework for you. Although it might take more effort to do the work on your own, you will profit more from your effort. We will be happy to evaluate your work though.
However, I will start you out.
90% = mean ± 1.645 SEm
95% = mean ± 1.96 SEm
SEm = SD/√n 
You are given the sample mean and the sample standard deviation. Use this information to construct the 90% and the 95% confidence intervals for the population mean. Which interval is wider? If convenient, use the technology to construct the confidence intervals
A random sample of 34 gas grills has the mean price of $649.30 and a standard deviation of $58.70
Construct a 90% confidence for the population mean:
The 90% confidence interval is
Construct a 95% confidence for the population mean:
The 95% confidence interval is