Question

The following data are from a simple random sample (The population is infinite):

Sample Size: 166

Sample Mean: 15.5

Population Variance: 138

If the Analysis was run as a two tailed test find the Margin of error ± using an alpha value =0.10 (Input the absolute value for the margin of error (that is if the answer is ± 3.1, input 3.1) , Use 2 decimals in your answer) Use the appropriate table.

Answer 1

Given:

Sample Size = n = 166

Sample Mean = = 15.5

Population Variance, 2 = 138

Standard deviation, = √138 = 11.7473

Significance level, = 0.10

At 0.10 significance level, the critical value of z is

Z/2 = Z0.10/2 = 1.645......(from z table)

Margin of error, E = Z/2 × /√n

= 1.645 × 11.7473/√166

= 1.645 × 0.9118

= 1.50

Therefore margin of error is 1.50 (try 1.49 if getting wrong)