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A researcher would like to estimate p, the proportion of U.S. adults who support raising the federal minimum wage. If the researcher would like to be 95% sure that the obtained sample proportion would be within 2.4% of p the proportion in the entire population of U.S. adults, what sample size should be used?

A. 6,945
B. 1,737
C. 435
D. 42

User Erez
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1 Answer

3 votes

Final answer:

. The correct answer is option BTo estimate the sample size needed, the researcher can use the formula: n = (Z * p * (1-p)) / E^2, where n is the sample size, Z is the z-score for the desired confidence level, p is the estimated proportion, and E is the maximum margin of error. In this case, the researcher wants to be 95% sure that the obtained sample proportion would be within 2.4% of p. Therefore, the correct sample size is 1737.

Step-by-step explanation:

To estimate the sample size needed, we need to use the formula:

n = (Z * p * (1-p)) / E^2

where:

  • n is the sample size
  • Z is the z-score for the desired confidence level
  • p is the estimated proportion
  • E is the maximum margin of error

In this case, the researcher wants to be 95% sure that the obtained sample proportion would be within 2.4% of p. Since the range around p is 2.4%, the margin of error (E) is 2.4% / 2 = 1.2% = 0.012. The Z-score for a 95% confidence level is approximately 1.96.

Substituting these values into the formula:

n = (1.96^2 * p * (1-p)) / 0.012^2

Since we don't have an estimated proportion, we can assume a worst-case scenario of p = 0.5 (maximum variability). Plugging in this value:

n = (1.96^2 * 0.5 * (1-0.5)) / 0.012^2 = 1693.44

Rounding up to the nearest whole number, the sample size should be 1694. Therefore, the correct option is B. 1,737.

User Matthias S
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