The average amount of precipitation in Dallas, Texas, during the month of April is 3.5 inches (The World Almanac, 2000). Assume that a normal distribution applies and that the standard deviation is .8 inches.
What percentage of the time does the amount of rainfall in April exceed 5 inches (to 2 decimals)?
What percentage of the time is the amount of rainfall in April less than 3 inches (to 2 decimals)?
A month is classified as extremely wet if the amount of rainfall is in the upper 10% for that month. How much precipitation must fall before a month of April is classified as extremely wet (in inches, to 2 decimals)?