Answer:
The minimum sample size required is 1809 computer users.
Major obstacle to getting a good estimate of the population mean is
b) It is difficult to precisely measure the amount of time spent on the internet
Explanation:
Minimum sample size can be found using the formula:
N≥
where
- N is the computer users surveyed
- z is the corresponding z-score for 95% confidence level
- s is the standard deviation of the population of monthly time spend on the internet
- E is the expected margin of error from the mean.
Here z=1.96, s=217 min. E=10 min. If we put these values in the formula we get
N≥
=1808.9≈ 1809
Major obstacle in the survey is that it is difficult to precisely measure the amount of time spent on the internet