I'm wishing I'd paid closer attention in stats class. I found this link that had information about RIT standard deviation. It says:
"At each grade the standard deviation (for reading) is between 14 and 15. That means that if a student takes the test repeatedly on the same day, his/her scores will fall within 7-7.5 points on either side of the reported RIT score. That represents the RIT range....
The (Math) standard deviations (sd) varied from a high of 16.69 RIT points in 8 th grade to a low of 10.93 RIT points in second grade in the fall."
So using the 2008 1st grade Reading Mean of 160 and SD of 15, my daughter's score is over 2 SD above the mean for reading. Using 2008 1st grade Math Mean of 164 and SD of 10.93, her score is over 2 SD above the mean for math.
Does that make sense or am I messing up applying stats?
http://www.illinoisnwea.org/NWEA-06/MAP_101-handout.pdf
