Question

Suppose a randomly selected sample of *n* = 62 men has a
mean foot length of *x* = 28 cm, and the standard deviation
of the sample is 3 cm. Calculate an approximate 95% confidence
interval for the mean foot length of men. (Round the answers to one
decimal place.)

to cm

Answer #1

Solution :

Given that,

sample size = n = 62

Degrees of freedom = df = n - 1 = 62 - 1 = 61

t_{
/2,df} = 2.000

Margin of error = E = t_{/2,df}
* (s /n)

= 2.000 * ( 3/ 62)

= 0.8

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

- E < < + E

28 - 0.8 < < 28 + 0.8

27.2 < < 28.8

95% confidence interval for the mean: **(27.2 ,
28.8)**

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