19A telecommunications company wants to estimate the proportion of households that would purchase an additional telephone line if it were made available at a substantially reduced installation cost. Data are collected from a random sample of 500 households. The results indicate that 120 of the households would purchase the additional telephone line at a reduced installation cost. Complete parts (a) and (b) below. <:> - a. Construct a 95% condence interval estimate for the population proportion of households that would purchase the additional telephone line. Dsnsm (Round to four decimal places as needed.) b. The margin of error e=|:| (Round to 3 decimal places as needed.) c. The critical value for the upper tail is D (Round to 2 decimal places as needed.) d. How would the manager in charge of promotional programs concerning residential customers use the results in (a)? O A. The manager can infer with 95% condence that the proportion of households in the sample that would purchase an additional telephone line is somewhere in this interval. . The manager can infer that 95% of households would purchase an additional telephone line. . The manager can infer that the true population proportion of households that would purchase an additional telephone line is somewhere in this interval 95% of the time. . The manager can infer with 95% condence that the population proportion of all households that would purchase an additional telephone line is somewhere in this interval