Question

If I have a mean of 20, a standard deviation of 8 and a sample size of 16, what is the upper 95% confidence limit.

Answer 1

Solution :

Given that,

Point estimate = sample mean = = 20

sample standard deviation = s = 8

sample size = n = 16

Degrees of freedom = df = n - 1 = 16 - 1 = 15

At 95% confidence level the t is ,

= 1 - 95% = 1 - 0.95 = 0.05

t _,df = t_0.05,15 = 1.753

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

= 1.753 * (8 / 16)

= 3.5

The upper 95% confidence limit is,

   + E = 20 + 3.5 = 23.5