Normal Distribution question

[sherry]

1. A test has a mean of 50, standard deviation of 10.

A. What scores separate the 25% from the rest?
B. What proportion would be expected to score between 45 and 55?
C. What proportion would be expected to score 68 and above
D. What proportion would be expected to score between 55 and 65 ?
E. What proportion score above 35?
F. What score separates the third on such test?

 

[stapel]

1. A test has a mean of 50, standard deviation of 10.

A. What scores separate the 25% from the rest?

Which 25%? The top 25%? The bottom? Something else?

B. What proportion would be expected to score between 45 and 55?

What did you get when you applied the z-score table with half a deviation?

C. What proportion would be expected to score 68 and above

How did you get started on this one?

D. What proportion would be expected to score between 55 and 65 ?

What value did you get for "everybody below 1.5 deviations"? What value did you get for "everybody below 0.5 deviations"?

E. What proportion score above 35?

How did you get started on this one, using 1.5 deviations again?

F. What score separates the third on such test?

Which third?

Please be complete. Thank you!