Let the following sample of 8 observations be drawn from a
normal population with unknown mean and standard deviation: 23, 26,
22, 20, 16, 21, 25, 24. [You may find it useful to
reference the t table.]
a. Calculate the sample mean and the sample
standard deviation. (Round intermediate calculations
to at least 4 decimal places. Round "Sample mean" to 3 decimal
places and "Sample standard deviation" to 2 decimal
places.)
Sample mean
Sample standard deviation
b. Construct the 90% confidence interval
for the population mean. (Round "t" value to
3 decimal places and final answers to 2 decimal
places.)
Confidence interval _____ to _____
c. Construct the 95% confidence interval
for the population mean. (Round "t" value to
3 decimal places and final answers to 2 decimal
places.)
Confidence interval _____ to _____
d. What happens to the margin of error as
the confidence level increases from 90% to 95%? (Choose one
option)
As the confidence level increases, the margin of error becomes
larger.
As the confidence level increases, the margin of error becomes
smaller.