Question

A sample of 28 observations is selected from a normal population where the sample standard deviation...

A sample of 28 observations is selected from a normal population where the sample standard deviation is 4.40. The sample mean is 16.40.  

a. Determine the standard error of the mean. (Round the final answer to 2 decimal places.)

The standard error of the mean is            .

b. Determine the 98% confidence interval for the population mean. (Round the t-value to 3 decimal places. Round the final answers to 3 decimal places.)

The 98% confidence interval for the population mean is between  and  .


c. If you wanted a narrower interval, would you increase or decrease the confidence level?

(Click to select)  Increase  Decrease

Homework Answers

Answer #1

Here, sample size , n = 28

sample mean , = 16.40 and smaple standard deviation , s = 4.40

a) The standard error of the mean = (s/n)

= 4.40 / (28)

= 0.83

b)Degrees of freedom = n -1 = 27

From the t critical values table we find the t value for df = 27 and 98% confidence level.

t = 2.473

The confidence interval is = t * s/n

= 16.40 2.056

= (14.344 , 18.456)

The 98% confidence interval for the population mean is between 14.344 and 18.456.

c)We know that, the width of the confidence decreases with decrease in confidence level. Therefore, if we want a narrower confidence interval, we would decrease the confidence interval.

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
A sample of 28 observations is selected from a normal population where the sample standard deviation...
A sample of 28 observations is selected from a normal population where the sample standard deviation is 5.00. The sample mean is 16.95.   a. Determine the standard error of the mean. (Round the final answer to 2 decimal places.) The standard error of the mean is. b. Determine the 95% confidence interval for the population mean. (Round the t-value to 3 decimal places. Round the final answers to 3 decimal places.) The 95% confidence interval for the population mean is...
A sample of 25 observations is selected from a normal population where the sample standard deviation...
A sample of 25 observations is selected from a normal population where the sample standard deviation is 4.85. The sample mean is 16.80.   a. Determine the standard error of the mean. (Round the final answer to 2 decimal places.) The standard error of the mean is            . b. Determine the 95% confidence interval for the population mean. (Round the t-value to 3 decimal places. Round the final answers to 3 decimal places.) The 95% confidence interval for the population...
A sample of 29 observations is selected from a normal population where the population standard deviation...
A sample of 29 observations is selected from a normal population where the population standard deviation is 40. The sample mean is 89.   a. Determine the standard error of the mean. (Round the final answer to 3 decimal places.) The standard error of the mean is  . b. Determine the 98% confidence interval for the population mean. (Round the z-value to 2 decimal places. Round the final answers to 3 decimal places.) The 98% confidence interval for the population mean is...
A sample of 23 observations is selected from a normal population where the sample standard deviation...
A sample of 23 observations is selected from a normal population where the sample standard deviation is 4.95. The sample mean is 16.90.   a. Determine the standard error of the mean. (Round the final answer to 2 decimal places.) The standard error of the mean is _______ . b. Determine the 90% confidence interval for the population mean. (Round the t-value to 3 decimal places. Round the final answers to 3 decimal places.) The 90% confidence interval for the population...
A sample of 25 observations is selected from a normal population where the population standard deviation...
A sample of 25 observations is selected from a normal population where the population standard deviation is 32. The sample mean is 77.   a. Determine the standard error of the mean. (Round the final answer to 3 decimal places.) The standard error of the mean is . b. Determine the 95% confidence interval for the population mean. (Round the z-value to 2 decimal places. Round the final answers to 3 decimal places.) The 95% confidence interval for the population mean...
2. From a normal population, a sample of 245 observations is selected. The population standard deviation...
2. From a normal population, a sample of 245 observations is selected. The population standard deviation is 28, and the sample mean is 17. a. Determine the standard error of the mean. (Round your answer to 3 decimal places.) STANDART ERROR OF THE MEAN: …..? b. Determine the 95% confidence interval for the population mean. (In your calculations: round your z/t value to 2 decimals, but round all other values to 3 decimals. Round your final answer to 3 decimal...
From a normal population, a sample of 230 observations is selected. The population standard deviation is...
From a normal population, a sample of 230 observations is selected. The population standard deviation is 26, and the sample mean is 18. a. Determine the standard error of the mean. (Round your answer to 3 decimal places.) b. Determine the 99% confidence interval for the population mean. (In your calculations: round your z/t value to 2 decimals, but round all other values to 3 decimals. Round your final answer to 3 decimal places.)
A sample of 235 observations is selected from a normal population with a population standard deviation...
A sample of 235 observations is selected from a normal population with a population standard deviation of 25. The sample mean is 20. Determine the standard error of the mean. (Round your answer to 3 decimal places.) Determine the 90% confidence interval for the population mean. (Use z Distribution Table.) (Round your answers to 3 decimal places.)
A sample of 250 observations is selected from a normal population with a population standard deviation...
A sample of 250 observations is selected from a normal population with a population standard deviation of 23. The sample mean is 18. Determine the standard error of the mean. (Round your answer to 3 decimal places.) Determine the 99% confidence interval for the population mean. (Use z Distribution Table.) (Round your answers to 3 decimal places.)
A sample of 245 observations is selected from a normal population with a population standard deviation...
A sample of 245 observations is selected from a normal population with a population standard deviation of 25. The sample mean is 20. Determine the standard error of the mean. (Round your answer to 3 decimal places.) Determine the 90% confidence interval for the population mean. (Use z Distribution Table.) (Round your answers to 3 decimal places.)
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT