What kind of survey (mail, telephone, interview, web, direct observation) would you recommend that a small laundry and dry cleaning business use for each of the following purposes, and why?

a.

To estimate the proportion of customers preferring opening hours at 7 a.m. instead of 8 a.m.

b.

To estimate the proportion of customers who have only laundry and no dry cleaning.

c.

To estimate the proportion of residents in the same zip code who spend more than $20 a month on dry cleaning.

d.

To estimate the proportion of its seven employees who think it is too hot inside the building.