Question

The 60% confidence interval on the mean

mean = 4.496207

sd = 1.139237

N = 29

Answer 1

Solution :

Given that,

Point estimate = sample mean = = 4.496207

sample standard deviation = s = 1.139237

sample size = n = 29

Degrees of freedom = df = n - 1 = 29 - 1 = 28

At 60% confidence level the t is ,

= 1 - 60% = 1 - 0.60 = 0.40

/ 2 = 0.40 / 2 = 0.20

t _/2,df = t _0.20,28 = 0.855

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

= 0.855 * (1.139237 / 29)

= 0.180876

The 60% confidence interval estimate of the population mean is,

- E < < + E

4.496207 - 0.180876 < <  4.496207 + 0.180876

4.315331 < < 4.677083

(4.315331 , 4.677083)