The following frequency distributionreports the electricity cost for a sample of 50 two-bedroom apartments in Albuquerque, New Mexico, during the month of May of last year.
Electricity Cost Frequency
$80 up to $100 3
100 up to 120 8
120 up to 140 12
140 up to 160 16
160 up to 180 7
180 up to 200 4
a. Estimate the meancost.
b. Estimate the standard deviation.
c. Use the Empirical Rule to estimate the proportion of costs within two standard deviations
of the mean. What are these limits?
The solution gives the details of calculation of mean and standard deviation of a given data. Empirical rule is applied to estimate the proportion of costs within two standard deviations of the mean.