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Data from a survey of 50 randomly selected customers found a mean age of 38.7 years...

  1. Data from a survey of 50 randomly selected customers found a mean age of 38.7 years and the standard deviation was 6.13 years. Given that t* = 2.01, calculate the 95% confidence interval for the mean?   
    1. (32.57, 44.83)
    2. (34.78, 44.60)
    3. (36.96, 40.44)
    4. (38.70, 44.83)
Math   Statistics-And-Probability   
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Answer #1

Solution :

sample size = n = 50

Degrees of freedom = df = n - 1 = 49

t /2,df = 2.01

Margin of error = E = t/2,df * (s /n)

= 2.01 * (6.13 / 50)

Margin of error = E = 1.74

The 95% confidence interval estimate of the population mean is,

- E < < + E

38.7 - 1.74 < < 38.7 + 1.74

36.96 < < 40.44

c. (36.96, 40.44)

(,)

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