Question

7. in an area. A sample survey is to be conducted to determine the mean family income The question is, how many families should be sampled? In order to get more information about the area, a small pilot survey was conducted, and the standard deviation dollars. of the sample was conducted to be five hundred Ine spoOnsor of the survey wants you to use the ninety-nine percent confidence coefficient. Further, if you find the sample mean family income to be ninety-five hundred dollars, for example, you want to be able to make a statement such as, I am ninety-nine percent certain that the population mean family income is in the interval between ninety-four hundred dollars and ninety-six hundred dollars.' eight hundred dollars, for example, you want to claim ninety-nine percent certainty that the true mean income will be between eighty-seven hundred dollars and eighty-nine hundred dollars. information given, INTERMEDIATE CALCULATIONS TO 2 DECIMAL PLACES!! (8 points) Or, if you find the sample mean to be eighty- Based on the ROUND ALL what size sample should be taken? d. 167 a. 166 e. none of the above b. 42 C. 416, 025

Answer 1

7. Standard deviation, σ = 500

Confidence coefficient = 0.99

Margin of Error, E = (Upper limit - Lower limit)/2 = (9600-9400)/2 = 100

Significance level, α = 1-CL =    0.01

Critical value, z = NORM.S.INV(0.01/2) = 2.5758

Sample size, n = (z * σ / E)² = (2.5758 * 500 / 100)² = 165.87 = 166

Answer a. 166

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8. Answer b, I and II are both false.