SOLUTION: Find the probability of the given value of x mean = 28 standard deviation = 6.5 and x equal or less than 20 I need simple steps I know the formula is z= x-u/o and plus or minus

Algebra ->  Probability-and-statistics -> SOLUTION: Find the probability of the given value of x mean = 28 standard deviation = 6.5 and x equal or less than 20 I need simple steps I know the formula is z= x-u/o and plus or minus      Log On


   



Question 515083: Find the probability of the given value of x
mean = 28 standard deviation = 6.5 and x equal or less than 20
I need simple steps I know the formula is z= x-u/o and plus or minus .5 but I do not seem to come out right we are using the standard normal distribution chart

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
20 is (8/6.5) or 1.231 (approx) standard deviations below the mean of 28

so the z-score you are looking for is -1.231

the probability is the fraction of the distribution at or below this score