Answer:
(a) The 95% confidence interval for the population mean stress level is (73, 83).
(b) Increasing the confidence level to 99% from 95% the margin of error would be greater than 5.
Step-by-step explanation:
The (1 - <em>α</em>) % confidence interval for population mean is:
The information provided is:
= 78
Confidence level = 95%
MOE = 5
(a)
Compute the 95% confidence interval for the population mean stress level as follows:
Thus, the 95% confidence interval for the population mean stress level is (73, 83).
(b)
The formula to compute the margin of error (MOE) is:
The margin of error is affected by:
- Standard deviation
- Sample size
- Confidence level.
On increasing the confidence level the critical value of <em>z</em> increases.
And if the critical value is increased then the margin of error will also increase.
Thus, increasing the confidence level to 99% from 95% the margin of error would be greater than 5.