For this assignment, you'll
be looking at a 15-item measure called the Attitude toward Women Scale
(Spence, Helmreich, & Stapp, 1974). The dataset
contains responses to this questionnaire from 201 college students, who
responded using a 1-7 Likert scale.
items need to be reverse-scored before reliability can be checked:
atw04, atw06, atw08, atw11, and atw14
- Open a new Google
Document and name it "PSY 220 Stats 2 [your last name]".
- Compute the reliability
of the scale with all the items included and write "The reliability
of the original 15-item scale was alpha = ____" in the document,
with your obtained alpha in the blank.
If you were really going to use the Attitude toward Women Scale in
a research project, you would not drop any of the items; you would use
the whole thing and report the alpha you computed above. We're only dropping
items and improving reliability as a statistical exercise.
- If any items have "Alpha
if item deleted" values greater than the alpha of the whole scale,
write down (in the document) the item with the highest "Alpha
if item deleted" value and then re-run the reliability analysis
after you take
that item out. Repeat this process until none of the items has an
"Alpha if item deleted" value greater than the alpha of the
whole scale. Do not take out all the offending items at once, but rather
remove the one that will help you the most, then re-run the reliability
analysis, and repeat. As you remove each variable, write down that
- Write down the final
list of items that will be in your scale.
You wouldn't report these in an article, but I'd like to see them for
this assignment to make sure you took out the right ones.
- Write "The 15-item
scale was reduced to a __-item scale to improve its reliability. The
final reliability of this scale is alpha = ___."
- Create a new variable called
ATW that is the mean of all the remaining items. Create a histogram
plot of this variable. Write down the standard deviation, mean, and
N of this variable.
- Share the document with
firstname.lastname@example.org and log out of Google Documents.