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Finding the value for rejection region using some kind of table...

by korr2221
Tags: kind, region, rejection, table
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Dec14-09, 02:18 PM
P: 20
I'm lost no how to find the cutoff rejection region and which table to use?

This is an example,

n 34
X-bar 10.3
s 3.1

98% Confidence Interval for is
10.3 2.33 x 0.5316
= (9.0632 , 11.5368)

H0: ≤ 9
H1: > 9

Tests Z-stat = 1.3 = 2.4452
Statistic 0.5316

Significance Level = 0.01

Rejection Region =
Tail = RIGHT
Cutt -Off = Z-alpha = 2.326
Decision = Reject H0

p-value = 0.0072

I understand how they reject H0, but I am lost how they got 2.326. I think it's in the Z-table but I'm not sure, can someone explain to me clearly. It would also help if you can tell me how to find 0.0072 for the p-value.
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Dec15-09, 07:42 AM
HW Helper
P: 1,361
I'm not sure how your Z table is set up - whether it gives only tail areas or cumulative probabilities.

If it gives tail areas (areas to the right of specific Z-values, do this: look through the AREAS for 0.01 - the associated Z-value will be 2.326

If your Z- table gives cumulative probabilities (areas of the form P(Z <=z)), look for the area that is closest to 0.99 (this is 1 - 0.01) - again, the Z-value should be 2.236.

Some tables only give the area between 0 and specified values of Z. If this is the case, look through the areas for the value closest to 0.49 - again, you should find Z = 2.236.

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