Is this a valid test? . Point out to your students that this ...

[tth]

Is this a valid test?
  .
  Point out to your students that this is actually a positive correlation as far as the validity is concerned.
 
  The only reason the negative sign appears is because in the ranking process, the highest score gets a 1 (a metrically low number) and the lowest score gets a 10 (a metrically higher number). Ask your students to rank order the test scores, and then again compute the Spearman, using only the two sets of ranks. At that point, that correlation of -.733 now has a positive sign.
 
 
 What will be an ideal response?

Question 2

Advanced topic: What is SSError?
 
  A) (37)2 + (77)2 + (117)2
  B) (57)2 + (77)2 + (97)2
  C) (35)2 + (77)2 + (119)2
  D) (59)2 + (79)2 + (99)2

[lucas dlamini]

Answer to Question 1

Yes the test has a high degree of validity. Point out to you students that this is actually a positive correlation as far as the validity is concerned. The only reason the negative sign appears is because in the ranking process, the highest score gets a 1 (a metrically low number) and the lowest score gets a 10 (a metrically higher number). Ask your students to rank order the test scores, and then again compute the Spearman, using only the two sets of ranks. At that point, the correlation -.733 now has a positive sign.

Answer to Question 2

C

[tth]

Thank you!

[lucas dlamini]

Happy to help