Question

If n=10, ¯xx(x-bar)=34, and s=4, find the margin of error at a 95% confidence level

Give your answer to two decimal places.

Answer 1

Solution :

Given that,

= 34

s =4

n = Degrees of freedom = df = n - 1 =10 - 1 = 9

a ) At 95% confidence level the t is ,

= 1 - 95% = 1 - 0.95 = 0.05

  / 2= 0.05 / 2 = 0.025

t /2,df = t0.025,9 = 2.262 ( using student t table)

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

= 2.262 * (4 / 10)

= 2.86