Question

The scores of eight grade students in a math test are normally distributed with a mean of 57.5 and a standard deviation of 6.5. From this data, we can conclude that 68% of the students recieved scores between
a)34 and 64
b)34 and 68
c)51 and 64
d)51 and 68

Answer 1

work out the z scores  for   51  and 54 
z1 = (51 - 57.5) / 6.5 = -1
z2 = (64  - 57.5)/6.5 = 1
from tables of normal distribution this value os 3413 + 3413  = 68.26%


so the answer is  c