This is a dosed book may use a sheet with formulas and a cal

This is a dosed book may use a sheet with formulas and a calculator. Show your work to receive full credit. The U.S. Census Bureau collects demographics concerning the number of people in families per household. The distribution of the number of people per household is: What proportion of U.S. households have four or more people? Calculate the mean number of people in families per household in the U.S. Calculate the variance and standard deviation of the number of people in families per household in the U.S. Determine the proportion of the distribution that is within two standard deviations of the mean.

Solution

a) ans -0.48 ( means 48% out of 100% of household)

b) the mean no. of people will be 4.5 per household.

c) variance will be =summation (x-xbar)^2/n-1

therefore variance will be = (2-4.5)^2+(3-4.5)^2+(4-4.5)^2+(5-4.5)^2+(6-4.5)^2+(7-4.5)^2/5 = 17.5/5 = 3.5

stdev =sqrt(variance) =sqrt (3.5) = 1.870829

d) mean +- 2stdev =

mean +2*stdev = 4.5 +2*1.870829 = 8.241657

mean -2*stdev =4.5-2*1.870829 = 0.758343

Therefore answer will be = 0.758343 to 8.241657