Reliability Assignment

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.

The following items need to be reverse-scored before reliability can be checked:

atw01, atw02, atw04, atw06, atw08, atw11, and atw14

  1. Open a new Google Document and name it "PSY 220 Stats 2 [your last name]".
  2. 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.

Note: 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.

  1. 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 variable.
  2. 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.
  3. Write "The 15-item scale was reduced to a __-item scale to improve its reliability. The final reliability of this scale is alpha = ___."
  4. 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.
  5. Share the document with and log out of Google Documents.