An electric utility has placed special meters on 10 houses in a subdivision that measures the energy consumed (demand) at each hour of the day. They are interested in the en- ergy demand at one specific hour, the hour at which the system experiences the peak consumption. The data from these 10 me- ters are as follows (in KW): 23.1, 15.6, 17.4, 20.1, 19.8, 26.4, 25.1, 20.5, 21.9, and 28.7.

If is the true mean peak demand for the ten houses in this group of houses having the special meters, estimate. Now suppose that the utility wants to esti- mate the demand at the peak hour for all 5,000 houses in this subdivision. Let & be this quantity. Estimate 9 using the data given above. Estimate the proportion of houses in the subdivi- sion that demand at least 20KW at the hour of system peak.