What is the value b such that Pb Z b 09634Solutionou need

What is the value b such that P(-b < Z < b) = 0.9634?

Solution

ou need to understand this.
Draw the normal curve.
You are told the probability between -b and b is 0.9634
That interval will be centered on the mean. So there
will be an area under the curve of 0.4817 to the right
of the mean and an equal area to the left of the mean.
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If you use a z-chart look for 0.4817 in the body of the
chart; find the corresponding z-value listed on the left
side of the chart.

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If you use a TI calculator go to DISTR; select InvNorm;
enter 0.5+0.4817 or 0.5-0.4817 to get z= +2.09 or z=-2.09
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Those are the b-values you are looking for.