posted by Victor on .
A company produces steel rods. The lengths of the steel rods are normally distributed with a mean of 121.2-cm and a standard deviation of 1.8-cm.
Suppose a rod is chosen at random from all the rods produced by the company. There is a 23% probability that the rod is longer than:
Enter your answer as a number accurate to 1 decimal place. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion in the smaller area (.23) and its Z score. Use the equation below.
Z = (score-mean)/SD