Question

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

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.

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 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 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 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 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 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 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 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 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 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

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 14 minutes ago

asked 30 minutes ago

asked 43 minutes ago

asked 53 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 3 hours ago

asked 3 hours ago