Question

An economist wants to estimate the mean per capita income (in thousands of dollars) for a major city in Californ Suppose that the mean income is found to be $21.3 for a random sample of 2817 people. Assume the populatio standard deviation is known to be $79. Construct the 98 % confidence interval for the mean per capita income i thousands of dollars. Round your answers to one decimal place. Keypad 1 Point Answer(How to Enter) Lower endpoint Upper endpoint:

Answer 1

solution:-

given that mean = 21.3

standard deviation = 7.9

sample n = 2817

98% confidence for Z is 2.33

confidence interval formula

=> mean +/- Z * standard deviation /sqrt(n)

=> 21.3 +/- 2.33 * 7.9/sqrt(2817)

=> 21.3 +/- 0.3

=> 21.0 , 21.6

lower endpoint = 21.0 upper endpoint = 21.6

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