Joe had a score of 72 on the Counseling Aptitude Scale, and the standard error of measurement of the scale is 3. Where would we expect Tom's true score to fall 99.5 percent of the time?

Question

Joe had a score of 72 on the Counseling Aptitude Scale, and the standard error of measurement of the scale is 3. Where would we expect Tom's true score to fall 99.5 percent of the time? 
a.71 to 73 
b. 69 to 75 
c. 66 to 78 
d. 63 to 81

Ms. Sue · Answer

I see you haven't resolved this question about whose score you want. Please check with your teacher about this. http://www.jiskha.com/display.cgi?id=1374878955

PsyDAG · Answer

Do you mean standard error (SEm) or standard deviation (SD).

SEm = SD/√n, but no n is indicated.

If you meant SD, then use this equation.

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.0025 or .4975) and its Z score.

With equation above, calculate score for both ± Z.

Peter · Answer

you must add or subtract the SEM 3 times. 72-9=63 72+9=81 d. 63-81