## A marketing researcher must determine how many telephone numbers she needs to order from a sample provider to complete a survey of ATM users

Question

A marketing researcher must determine how many telephone numbers she needs to order from a sample provider to complete a survey of ATM users. The goal is to complete 400 interviews with ATM users. From past experience, she estimates that 70 percent of the phone numbers provided will be working phone numbers. The estimated incidence rate (percentage of people contacted who are ATM users) is 45 percent. Finally, she estimates from previous surveys that 37 percent of the people contacted will agree to complete the survey. How many telephone numbers should she order to complete the 400 interviews

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7 months 2021-08-17T07:42:16+00:00 1 Answers 0 views 0

the required number of telephone orders to complete the 400 interviews is 3433

Step-by-step explanation:

Given the data in the question;

Let us represent the telephone numbers the researcher orders to complete the 400 interviews with Y.

Thus, The working phone numbers = 70% × Y

Now, number of ATM users = 45% × The working ph0ne numbers

⇒ 45% × ( 70% × Y )

number of ATM users = 0.45 × 0.70 × Y = 0.315Y

Thus; Number of people contacted that agrees to complete the survey will be;

⇒ 37% × number of ATM users

⇒ 0.37 × 0.315Y = 0.11655Y

so, since the researcher needs at least 400 interviews

Hence;

0.11655Y ≥ 400

Y ≥ 400 / 0.11655

Y ≥ 3432.0034 ≈ 3433

Therefore, the required number of telephone orders to complete the 400 interviews is 3433