A random sample of 40 students is collected and the number of credit hours taken is...

A random sample of 40 students is collected and the number of credit hours taken is recorded. The sample mean is computed to be 12.5 hours with a standard deviation of 3 hours. Construct a 95% confidence interval for the mean credit hours taken. Follow 4-step procedure.

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Expert Solution

Solution :

Given that,

Point estimate = sample mean = = 12.5

Population standard deviation = =3

Sample size n =40

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z/2 = Z0.025 = 1.96 ( Using z table )

Margin of error = E = Z/2 * ( / $\sqrt$ n)
= 1.96 * (3 / $\sqrt$ 40 $\sqrt$ )

= 0.93
At 95% confidence interval mean
is,

- E < < + E

12.5- 0.93 < < 12.5+ 0.93

(11.57,13.43 )

orchestra answered 1 year ago

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