Z-Test for Mean when Variance is Known

 

Examples From:
Statview
JmpIn
Minitab
Excel
Java Applet


  
 

Statview

Statview will not directly perform this statistical test. Use the one-group t-test (discussed in the next chapter), which will produce approximately the same answer.

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JmpIn

Under the ANALYZE menu select DISTRIBUTION, then select the variable. Then select the option for "Testing Mean = ", which will open the following dialog box. Enter the mean to be tested (in this case, "10") and the known standard deviation (in this case, "2.236").

JMP dialog box for z-test

which produces:

z-test from JMP

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Minitab

MTB > ZTest 10 2.24 'SKQ-Pre';
SUBC>   Alternative 1.

produces: 

Test of mu = 10.000 vs mu > 10.000
The assumed sigma = 2.24

Variable     N      Mean    StDev   SE Mean        Z    P-Value
SKQ-Pre     15    11.533    2.200     0.578     2.65     0.0041

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Excel

Excel will not directly perform this statistical test with the tools available in the Data Analysis toolpack. Download ztest.xls, an Excel worksheet that will perform the z-test for the mean when the variance is known.

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Java Applet

The following Java applet introduced on the main page calculates the z-test and its probability.

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File:
© 1999, Duxbury Press.