SOLUTION: A normal population has a mean of 55 and a standard deviation of 13. You select a random sample of 25. Compute the probability the sample mean is: (Round z values to 2 decimal p

Question 925688: A normal population has a mean of 55 and a standard deviation of 13. You select a random sample of 25.
Compute the probability the sample mean is: (Round z values to 2 decimal places and final answers to 4 decimal places.)
(a) Greater than 59.
Probability =
(b) Less than 51.
Probability =
(c) Between 51 and 59.
Probability =

Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
mean = 55, SD = 13 , n = 25 z =
...
Using the z-value to determine the Probability:
P(x > 59) = P(z > 4/2.6) = P(z > 1.54) = 1 - P(z < 1.54) = .0618
Using a TI calculator 0r similarly a Casio fx-115 ES plus
P(z > 1.54) = normalcdf(1.54,100) = .0618
.............
P(x < 51) = P( z < -4/2.6) = P( z < -1.54) = normalcdf(-100, 1.54) = .0618
......
P(51 < x < 59) = P( -1.54 < z < 1.54) = 1 - .0618 - .0618 = .8764
Or
Using a TI calculator 0r similarly a Casio fx-115 ES plus
P( -1.54 < z < 1.54) = normalcdf(-1.54, 1.54)= .8764
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