Question

The TI84 Graphing Calculator can be used with the normal probability distribution.

normalcdf( will find the area or probability

invNorm( will find the z-score or x-value from a given probability

Solve the following 2 problems and discuss the difference between the 2 graphing calculator functions mentioned above.

1. The random variable x has a normal distribution with a mean of 64.7 and standard deviation of 6.8. Find the probability that x is greater than 58.1.

2. The random variable x has a normal distribution with a mean of 64.7 and standard deviation of 6.8. Find the cut-off value of x for the bottom 40%.

Answer 1