PROBLEM ONE: INDEPENDENT SAMPLES T TEST

The new chief of police in Cleveland, Mississippi, is interested in determining whether there is any difference in performance between the new Springfield XD firearm and the older Glock firearm.  The chief has taken 10 officers and divided them into 2 groups of 5 each.  The first group will fire 10 rounds at 14 targets from the Glock.  The second group will fire 10 rounds at 14 targets from the Springfield.  The results are located in the data file Firearms.sav. 

Steps for running the Independent Samples t test:

Open the data file

From the top of the menu Select Analyze

Highlight Compare Means

Select Independent Samples t test

When the “Independent-Samples t test” box opens:

Select the variable score and select the arrow next to Test Variable(s)

Select the variable group and select the arrow next to Grouping Variable

Select the Define Groups option

When the “Define Groups” box opens:

Type “0” next to group 1

Type “1” next to group 2

Select Continue

Click OK

 

PROBLEM TWO: PAIRED SAMPLES T TEST

The chief of police from the above example decides that there is the possibility that the difference between groups is attributable to previously gained skills.  To test this hypothesis the chief decides to run the firearms test again.  This time, however, the chief decides to select only 5 officers and have each officer fire both weapons.  The results of the test are presented in the data file Firearms2.sav.

Steps for Running the Dependent Samples T Test:

Open the Data File

From the top of the menu select Analyze

Highlight Compare Means

Select Paired Samples t test

When the “Paired Samples t Test” Box appears:

Select the glock variable

Select the sprgfiel variable

Select the arrow next to “Paired Variables”

Both variables will move into the box

Select OK

 

PROBLEM THREE: ONE SAMPLE T TEST

The chief of police from the above examples has decided that based upon the previous tests he is going to implement the Springfield into his department.  As one final test he selects 10 new officers who will test fire the Springfield.  The results are then to be compared to the average score provided by Springfield (112).  The results of the test are presented in the data file Firearms3.sav.

Steps for Running the One Sample T Test:

Open the Data File

From the top of the menu select Analyze

Highlight Compare Means

Select One Sample t Test

 

When the “One-Sample T Test” box opens:

Select the variable score

Select the arrow next to the “Test Variable(s)” box

In the Test Value box type “112”

Select OK