Probability based on normal distribution.
An accounting firm is planning for the next tax preparation season. From last year's returns, the firm collects a systematic random sample of 100 filings. The 100 filings showed an average preparation time of 90 minutes with a standard deviation of 140 minutes.
1. What is the likelihood that the mean completion time will be more than 120 minutes?
2. What is the possibility that the mean completion time is between 1 and 2 hours, to be exact 60 and 120 minutes?