In: Statistics and Probability
For a normal population with known variance σ2, what value of zα/2 in the Equation below gives a 98% CI?
x-zα/2σn≤μ≤x+zα/2σn
solution:
At 98% confidence level the z is ,
= 1 - 98% = 1 - 0.98 = 0.02
/ 2 = 0.02/ 2 = 0.01
Z/2 = Z0.01 = 2.326 ( Using z table )
Margin of error = E = Z/2
* (
/n)
At 98% confidence interval
is,
- E < < + E
- Z/2 * ( /n) < < + Z/2 * ( /n)
- 2.326 * ( /n) < < + 2.326 * ( /n)