Summary
Summary 2.5P Practical Psychometrics: An Introduction
- Course
- Institution
Practical Psychometrics: An Introduction. Summary and explanation of all the SPSS commands covered in the examples and lectures
[Show more]
Seller
Follow
gg12121
Reviews received
Content preview
2.5 SPSSSession 1: transformations & percentile ranks
➔ Calculating scale scores of test:
◆ transform– compute variable–all– mean
● put the 1st question and last question (Q1 to Qn) that will be included in
the analysis
● add .N— how many questions minimum should be answered for the
participant's score to be included (22)
● then, multiply the whole thing by number of questions/items in the test
(30)
● if you want, RND to get rid of the decimals
◆ go to analyze– descriptives to calculate the average scale score
➔ Bar chart of average scale scores
◆ graphs– legacy dialogues– bar– simple– define
● bars represent: other statistic
○ choose variable: scale score
○ can change the statistic (mean, median, standard deviation etc.)
● category axis: gender (the grouping variable)
,➔ calculate z-scores
◆ analyze— descriptives— click “save standardized values as variables”
➔ calculating mean difference between 2 groups as t-value
◆ analyze— compare means— independent samples t-test
● choose test variable (z score of scale scores)
● choose grouping variable (this is the 2 groups we will compare; gender) &
define groups
, ● look at the Levene’s test for which t-value to use:
○ Levene’s test is significant= equal variance not assumed
○ Levene’s test is not significant= equal variance assumed
○ t-value= 2.65
➔ calculating probability of scoring below a certain score (assuming normal distribution)
◆ transform— compute variable— CDF.NORMAL
● put in (variable, mean, standard deviation)
● we can use the z_scores of scale values because its mean and
standardized deviation is known (1,0)
● find your desired value and look at the associated p_value
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller gg12121. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.54. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
70055 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now