I’m going to use this example to
help you understand how to enter the data. Suppose you want to study the
effect of sugar (IV) on memory for words (DV). You have three groups (also
called conditions) in your experiment, sugar, a little sugar and no
sugar. Each participant only participates in one condition of the
experiment. Participants in the first condition are not related in any way
to participants in the second condition or third condition. Because the
participants in each condition are not related in any way, we will use the
1-Way Between Subjects ANOVA. Here are the data.
Condition 1: Sugar |
Condition 2: A little Sugar |
Condition 3: No Sugar
|
Participant 1 = 3 words
Participant 2 = 6 words
Participant 3 = 4 words
Participant 4 = 3 words
Participant 5 = 5 words |
Participant 1 = 3 words
Participant 2 = 5 words
Participant 3 = 3 words
Participant 4 = 3 words
Participant 5 = 4 words |
Participant 1 = 2 words
Participant 2 = 2 words
Participant 3 = 1 words
Participant 4 = 3 words
Participant 5 = 3 words |
In this experiment, you want to know
if there is a significant different between the data collected from each
condition, sugar, a little sugar and no sugar. You want to know if sugar
really does have an effect on memory for words. Does word memory
significantly increase or decrease when people eat sugar? Is there no
difference in word memory for sugar and no sugar conditions?
Just looking at the data, you can
probably see that there is a difference in word memory between the three
conditions. You can probably see that word memory in the sugar condition
appears to be much better than word memory in the no sugar condition. Word
Memory in the a little sugar condition also appears to be better than that
in the no sugar condition. People generally appear to remember more words
when they have eaten sugar. So you might be wondering, why can’t I just look
at the data? Why do I have to conduct this t-test? The reason is that we are
not just trying to figure out if there is a difference in words recalled
between each group. We want to know if there is a statistically
significant difference. That is, a real difference as defined by
statistics. The ANOVA will be able to tell us that.
Two columns of data
You will use the first two columns
of your SPSS data file to enter the data for the 1-Way Between Subjects
ANOVA.
In this column, you should type in
three different numbers to represent each of your three conditions. For
example, you could use the numbers 1, 2 and 3 to represent your three
conditions. The 1s could be used to represent the sugar condition and the 2s
could be used to represent the a little sugar condition. The 3s could be
used to represent the no sugar condition. Take a look at what I’m talking
about below. You can see one column of data with 1s, 2s and 3s. There are
five 1s. They will represent data from the five participants in the first
condition, sugar. Below the 1s are five 2s. They will represent data from
the five participants in the second condition, a little sugar. There are
also five 3s. They will represent the data from the five participants in the
third condition, no sugar. The number of 1s, 2s and 3s that you use will
vary, depending on how many participants you have in each condition.

Double click on the top of the first
column to name it. The Define Variable box will pop up and you can enter a
new name for the variable in the Variable Name area. Give the column a
meaningful name. This will make your life a lot easier when you analyze the
data and interpret the results. Because this column represents the three
conditions of the IV, it is a good idea to use the letters “IV” in the name
of the variable. You might also want to include a word that describes what
is being manipulated. In the below example, I decided to name my variable “IVsugar.”
I decided on this name because this variable is an IV in which the presence
of sugar is being manipulated. Hold off on clicking OK when finished. We are
going to do something else with the Define Variable box before we close it.
Life would be a lot easier if the
numbers 1, 2 and 3 in the first column of the data file had meaningful
names. While we can’t type in meaningful names directly into the data file,
we can convert these numbers to meaningful names. To do this, click on the
Labels button in the Define Variable box. A Define Labels box will appear.

You will see three blanks that will
be important to fill in.

In the Variable Label box, enter the
word “IV levels.” In the Value box, enter the number 1. This number
represents the first condition of your experiment. In the Value Label box,
enter a meaningful name for the first condition of your experiment. In this
example, I have chosen the word “Sugar” to name the first condition. Click
the Add button when you are finished.

You will see the phrase 1.00 =
“Sugar” appear in the large bottom window. This means that SPSS knows
that the number 1 that you used in the data file represents the condition
“Sugar.”

Now that you have entered
information for condition 1, continue with condition 2. Do nothing with the
Variable Label box. Type the number 2 into the Value box. Type a meaningful
name for condition 2 in the Value Label box. In my example, I chose the name
“A little sugar” to represent my second condition. When you are finished,
click the Add button.

Similar to before, do nothing with
the Variable Label box. Enter a number 3 in the Value box to represent the
third condition. Enter a meaningful name for the third condition into the
Value Label box. In this example, I chose the name “No sugar” to represent
by third condition. Click the Add button when you are finished.

You will see all three condition
number and names appear in the bottom window of this box. Each condition
name is paired with a corresponding number in the data file. Click the
Continue button when you are finished.

You will return to the Define
Variable box. Simply click OK to exit.

Check out your data file. Look’s a
little different from the last time that you saw it. Now, instead of seeing
the numbers 1, 2 and 3 in the first column, you will see the words that
represent each of these conditions. You may think that this was an awful lot
of steps to take, just to get to the end result of seeing your conditions
labeled in the data file. Actually, you will benefit in the future from
labeling your conditions here. These labels will also appear in your results
file. They will make your results much easier to interpret.
Note that if you have completed all
of the previous steps but do not see the words instead of the numbers, you
are probably working on an older version of SPSS. That’s ok. Just continue.
While your conditions won’t be named in the data file, they will be named in
the results file and you will benefit from that.

In this column, you should type in
the actual data collected for each participant in each condition. In the
example, each data point represented the number of words remembered.
Start by entering the data from the
first condition of your experiment into the second column of the data file.
In this example the first condition was sugar. Each data point from the
sugar condition should be typed next to the word Sugar from the first
column. See the number 3 in the first row. That 3 represents three words
that the first participant in the Sugar condition remembered.

When you are finished entering the
data from the first condition, continue on by entering the data from the
second condition. It’s easy to enter the data in the right spot because we
have the condition names in the first column. See that 3 next to the first
“A little sugar” label? That represents the number of words remembered by
participant 1 in the “A little sugar” condition.

Finally, enter the data from the
third condition of your experiment. See that 2 next to the first “No Sugar”
label? That represents the number of words remembered by participant 1 in
the “No Sugar” condition.

Name
the second column
Double click on the top of the
second column to name it. Enter a name into the variable name box. The
second column represents your DV. Because of this, it’s a good idea to
include the letters “DV” in the name of the second column. It is also a good
idea to include the name of what is being measured. Since words are being
measured in this example, I decided to name my variable “dvwords.” Click OK
when you are finished.

But don’t forget to save the data
file to a meaningful place with a meaningful name. I decided to name my data
file “Effect of Various Amounts of Sugar on Words Remembered Data.sav.” It’s
a long name but this file will be very easy for me to identify in the
future. See how I used the word “Data” in the name? This will help me to
know that this is my data file in the future, as compared to my output file
which might have a similar name.

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