Dot miller owns a small chain of dive shops. she is interested in knowing how many potential customers she will need to sample in several large cities within a three- to four-hour drive of her shops located on the california coast. she wants to estimate the mean response to a 10-point scale measuring the likelihood that they will subscribe to a dive package which, if they take advantage of all the dives, represents a savings of 50 percent over taking the dives individually. in estimating the standard deviation in the population for the formula for calculating the sample size for estimating a mean, dot can: rely on the knowledge of other owners in the dive industry to share their knowledge of surveying scuba divers. use some prior knowledge about the population, undertake a pilot study or estimate the range, and divide by 10. use some prior knowledge about the population, undertake a pilot study or estimate the range (7), and divide by 6. undertake a pilot study using members of the dive population who live near the present dive shops. none of these; if you do not have the actual standard deviation, you cannot use the formula.