Question

Given the sample results taken from a normal population distribution: mean = 4.65, σ = 0.32, and n = 19.
For a 90% confidence interval, find the margin-of-error for the population mean. (use 2 decimal places)

Answer 1

Solution :

Given that,
Population standard deviation =    = 0.32
Sample size = n =19

At 90% confidence level

= 1 - 90%  

= 1 - 0.90 =0.10

/2 = 0.05

Z/2 = Z0.05 = 1.645

Margin of error = E = Z/2    * ( /n)

=1.645 * ( 0.32/  19 )

E= 0.12