Given a mean of 61.2 and a standard deviation of 21.4, within how many standard deviations of the mean do the values 45,78,62,90, and 31 fall? a.0 b.1 c.2 d.3

Determine the number of standard deviations that needs to be subtracted from or added to the mean in order to arrive to the values given.
  
(1) 45 = 61.2 - 21.4n   ; n = 0.757
(2) 78 = 61.2 + 21.4n  ; n = 0.785
(3) 62 = 61.2 + 21.4n  ; n = 0.037
(4) 90 = 61.2 + 21.4n   ; n = 1.346
(5) 31 = 61.2 - 21.4n    ; n = 1.4

Therefore, the answer for 45 and 78 is approximately 1 (letter b), for 62 is zero (letter a), and for the last two numbers, more than 1 or two (letter c).