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KuderRichardson #21 Formula for estimate test reliability
Good Morning!
I am trying to figure out how to adapt the KruderRichardson Formula #21 to excel. First of all this is not a homework assignment. Secondly, I appologize for linking a file but I could not get the fonts for the formula right. What the formla does is to estimate test reliability. I can figure it out long hand but would greatly appreciate it in excel thanks in advance. R=( k) (1 X(kX))   k1 kS where R= test reliability k = number of items on the test X = mean of raw scores from the total test S = vfariance from the raw scores of the total test Suppose we had a 50 item test and the mean score was 43 and the variance was 25.0. We would have R= (50) (1 43(50  43))   501 (50)(25) R = (1.02) (1 301)  1250 R = (1.02) (0.76) = 0.78 Thank you in advance. http://www.savefile.com/projects/808560688 
#3




KuderRichardson #21 Formula for estimate test reliability
Hello,
If you google for "KuderRichardson 21 Formula excel" then you will find http://www.gifted.uconn.edu/siegle/r...eliability.htm which links to a [IMHO] nice sample spreadsheet http://www.gifted.uconn.edu/siegle/r...alculator2.xls Some things are easier copied than reinvented. Regards, Bernd 
#4




KuderRichardson #21 Formula for estimate test reliability
A caveat 
There are tens of thousands of workbooks out there that can be copied. A significant fraction of them, including ones posted by academics, have errors or have poor boundary event error checking. Validating someone else's worksheet for a simple calculation like this can often be *more* difficult than building from scratch... In article . com, Bernd P wrote: Some things are easier copied than reinvented. 
#5




KuderRichardson #21 Formula for estimate test reliability
On Nov 4, 10:48 am, JE McGimpsey wrote:
A caveat  There are tens of thousands of workbooks out there that can be copied. A significant fraction of them, including ones posted by academics, have errors or have poor boundary event error checking. Validating someone else's worksheet for a simple calculation like this can often be *more* difficult than building from scratch... In article . com, Bernd P wrote: Some things are easier copied than reinvented. Hide quoted text   Show quoted text  Thank you both! 
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