An investigator polls a representative sample of common cold sufferers, asking them to estimate the number of hours of physical discomfort caused by their most recent cold. Their estimates approximate a normal curve with a mean of 83 hours and a standard deviation of 20 hour.

6.What percentage of sufferers estimate that their colds lasted for longer than forty-eight hours?

1. What percentage suffered for fewer than 61 hours?
2. What percentage suffered for between one and three days?
3. Inverse Normal Distribution: What is the estimated number of hours for the shortest-suffering 10 percent?
4. Inverse Normal Distribution: A medical researcher wishes to concentrate on the 20 percent who suffered the most. She will work only with those who estimate that they suffered for more than _____hours.