17.19 In the survey of Exercise 17.17, the households were asked if they had cable television. The numbers having cable are given in the accompanying table.

Precinct 1 2 3 4 5 6 7 8 9 10 Number 12 11 10 29 15 13 20 14 9 26

a. Find a point estimate of the proportion of all households in the city having cable television.

b. Find a 90% confidence interval for this population proportion.