# Question: Again consider the survey of 350 Bank of America customers

Again consider the survey of 350 Bank of America customers discussed in Exercise 7.29, and assume that 48% of Bank of America customers would currently express customer delight. That is, assume p = .48. Find:

a The probability that the sample proportion obtained from the sample of 350 Bank of America customers would be within three percentage points of the population proportion. That is, find P(.45 ≤ p̂ ≤.51).

b The probability that the sample proportion obtained from the sample of 350 Bank of America customers would be within six percentage points of the population proportion. That is, find P(.42 ≤ p̂ ≤.54)

a The probability that the sample proportion obtained from the sample of 350 Bank of America customers would be within three percentage points of the population proportion. That is, find P(.45 ≤ p̂ ≤.51).

b The probability that the sample proportion obtained from the sample of 350 Bank of America customers would be within six percentage points of the population proportion. That is, find P(.42 ≤ p̂ ≤.54)

## Relevant Questions

Based on your results in Exercise 7.30, would it be reasonable to state that the survey’s “margin of error” is +-3 percentage points? + - 6 percentage points? Explain. Explain why it is important to calculate a confidence interval. The bad debt ratio for a financial institution is defined to be the dollar value of loans defaulted divided by the total dollar value of all loans made. Suppose a random sample of seven Ohio banks is selected and that the ...Explain exactly what we mean when we say that a sample of size n makes us 99 percent confident that x̅ is within E units of μ. Suppose we are using the sample size formula in the box on page 313 to find the sample size needed to make the margin of error in a confidence interval for p equal to E. In each of the following situations, explain what ...Post your question