in order to estimate the average time spent on the computer terminals per student at a local university, data were collected from a sample of 81 business students over a one-week period. assume the population standard deviation is 1.2 hours.
The standard error of the mean is?
a. 7.5
b. 0.014
c. 0.160
d. 0.133
With a 0.95 probability, the margin of error is approximately?
a. 0.26
b. 1.96
c. 0.21
d. 1.64
If the sample mean is 9 hours, then the 95% confidence interval is approximately?
a. 7.04 to 110.96 hours
b. 7.36 to 10.64 hours
c. 7.80 to 10.20 hours
d. 8.74 to 9.26 hours