##### Question

In: Statistics and Probability

# For a normal population with known variance σ2, what value of zα/2 in the Equation below...

For a normal population with known variance σ2, what value of zα/2 in the Equation below gives a 98% CI?

x-zα/2σnμx+zα/2σn

## Solutions

##### Expert Solution

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)

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