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Welcome
 Welcome to Inferential Statistics with R
 Introduction to the Dataset

ttests
 Independent ttest
 Dependent ttest

OneWay ANOVA
 OneWay ANOVA
 Post Hoc Comparisons
 Other ANOVA Tests

ChiSquare
 ChiSquare
 Dealing with Small Cells

Correlation
 Correlation

Regression
 Linear Regression
 Multiple Regression
 Hierarchical Regression

Reliability
 Reliability

Reporting Results
 Extracting Output
 Reporting Results

Testing Assumptions
 Testing Assumptions
 Testing for Normality
 Testing for Homogeneity of Variance
 Violated Assumptions
Inferential Statistics with R
Reliability
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This lesson is called Reliability, part of the Inferential Statistics with R course. This lesson is called Reliability, part of the Inferential Statistics with R course.
Transcript
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Your Turn
Perform a test of internal consistency using both omega and alpha on the SWLS scale at time 2.
Does the scale have good internal consistency at time 2, as well?
Learn More
Read more about the omega() and alpha() functions in the psych package.
The Personality Project also has a great tutorial on Using R and the psych package to find omega.
Interested in learning more about why it may be preferential to use omega instead of alpha? Check out the article "Thanks coefficient alpha, we'll take it from here " by McNeish (2018). Use this link to download the unformatted open access version of the article.
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Maria Cristina Limlingan
January 13, 2022
Thanks for sharing about omega  this is good information to know. I'm wondering if you suggestions about how to do inter rater reliability between two people in R? (e.g. 2 people doing an observation and want to find out if they are coding similarly)
Dana Wanzer
January 14, 2022
There's a couple packages that can do it, including irr and tidycomm. For a previous project of mine, I went with tidycomm (using the test_icr function) because we had missing data and more than 2 coders, plus it can calculate a wide variety of IRR values. https://cran.rproject.org/web/packages/tidycomm/tidycomm.pdf
Maria Cristina Limlingan
February 10, 2022
Thanks for the suggestion Dana! I used the tidycomm package and got it to run  but I wanted to make sure if the way I structured the file was right  do you have an example of how the data should look like in R? Also, just in case you had some thoughts  if the data we are trying to check reliability is nominal/categorical  I read the Hayes and Krippendorff paper below and based like that is Krippendorff the recommended alpha you would use? Thanks in advance for your help! Hayes, A. F., & Krippendorff, K. (2007). Answering the Call for a Standard Reliability Measure for Coding Data. Communication Methods and Measures, 1(1), 77–89. https://doi.org/10.1080/19312450709336664
Dana Wanzer
February 10, 2022
This vignette from the package does a good job of showing how the data needs to be structured: https://cran.rproject.org/web/packages/tidycomm/vignettes/v04_icr.html
And yes, my understanding is to use Krippendorff's alpha if you have missing data or ordinal/interval/ratio level of measurement in the coding.