3.10. Exersizes#
Given the data set that represents a sample: 7, 15, 92
Determine the following (work must start from the governing equation)
a. mean
b. standard deviation
Given the data set: 5, 30, 7, 18
Determine the following:
a. mean
b. median
c. standard deviation
d. variance
The low-density lipoprotein (LDL) cholesterol concentration for a group has a mean of 140 mg/dL and a standard deviation of 40 mg/dL. What percentage of the group will have LDL values greater than 200 mg/dL? Assume a normal distribution, draw a “bell curve” and shade and label the area of interest.
The mean annual precipitation for Portland, Oregon over 5 years was found to be 36.2 inches (in.) with a standard deviation of 7.8 in. Assume that the precipitation follows a normal distribution. Use the z-table in the appendix and round appropriately to the precision provided in the table.
Determine the following values and draw a sketch labeled with the mean and point of interest and shade the area of interest to represent each.
a. The probability that the precipitation in any given year is greater than 48.0 in.
b. The probability that the precipitation in any given year is less than 20.3 in.
c. The probability that the precipitation in any given year is between 40.0 and 60.0 in.
At cruising altitude, a commercial jet engine consumes an average of 945 gallons of fuel per hour with a standard deviation of 52 gal per hour. Assume that the fuel consumption follows a normal distribution at cruising altitude. Use the Z-table in the appendix and round your final answers to the precision provided in the table.
Determine the following values and draw a sketch labeled with the mean and point of interest and shade the area of interest to represent each.
a. The probability that the hourly fuel consumption is between 800 and 1000 gallons
b. The probability that the hourly fuel consumption is less than 950 gallons
c. If the cost for fuel for the commercial jet engine is $0.85 / gallon, and the aircraft cruises 225 hours per month, what is the probability that the monthly cost of fuel exceeds $150,000?