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)