Mean = 28 Standard Deviation = 8 Data is normally distributed
1) (26-28) / 8 = -0.25 (LOWER)
(34 - 28) / 8 = +0.75 (UPPER)
Using NORMALCDF --> 37.2%
2) (26-28) / 8 = -0.25 (UPPER)
Since there is no LOWER we use -1E99 (negative infinity)
Using NORMALCDF --> 40.1%
3) INVNORM(0.95) = +1.64 --> We use this since we want the farther right 5%, so 95% to the left
x = (1.64)(8) + 28 = 41.12 = 42 (Rounded)
4) INVORM(0.4) = -0.25 INVNORM(0.6) = +0.25 --> Remember the symmetry
(Since the middle 20% is 10% on both sides of the mean, that leave 40% of the data below the LOWER
x = (-0.25)(8) + 28 = 26 x = (+0.25)(8) + 28 = 30