Question

Find out the 95% confidence interval for a sample whose Mean=10.50 and Standard Deviation is= 2.0. The sample size is n=50.

** please I need the answer in the computer typing not hand writing.

Subject: Statistic

Answer 1

Solution :

Given that,

Point estimate = sample mean = = 10.50

Population standard deviation =    = 2.0

Sample size = n =50

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z_/2 = Z_0.025 = 1.96

Margin of error = E = Z/2 * ( /n)

=1.96 * (2.0 /  50 )

= 0.5544
At 95% confidence interval estimate of the population mean
is,

- E < < + E

10.50 -0.5544<   < 10.50 + 0.5544

99.4560 <   < 11.0544

( 99.4560 , 11.0544 )