Assuming a normal distribution, where would you find ...

[Deast7027]

Assuming a normal distribution, where would you find approximately two thirds of the scores if they ranged from 30 to 68, M = 45, and SD = 7? Between:
 
  a. 30 and 68
  b. 31 and 59
  c. 37 and 61
  d. 38 and 52

Question 2

What percent of scores will be within one standard deviation above or below the mean?
 
  a. 34
  b. 68
  c. 95
  d. 99

[elizabethrperez]

Answer to Question 1

ANS: D
In the normal curve, 68 of scores will be within one standard deviation above or below the mean. In the example, two thirds of scores (66) fall between 30 and 68. The mean = 45 and the SD = 7 for this sample. It follows that scores will fall between one standard deviation below (45  7 = 38) and one standard deviation above the mean (45 + 7 = 52).

Answer to Question 2

ANS: B
In the normal curve, 68 of the scores will be within one standard deviation above or below the mean.

[Deast7027]

Thanks for the timely response, appreciate it

[alvinum]

TYSM