Use the 68-95-99.7 Rule to find probabilities or cutoff values.
-Based on data collected from its production processes, Crosstiles Inc. determines that
The breaking strength of its most popular porcelain tile is normally distributed with a
Mean of 400 pounds per square inch and a standard deviation of 12.5 pounds per square
Inch. Based on the 68-95-99.7 Rule, about what percent of its popular porcelain tile will
Have breaking strengths greater than 412.5 pounds per square inch?
A) 95%
B) 68%
C) 16%
D) 32%
E) 47.5%

Question

Quizplus · Accepted Answer

According to the 68-95-99.7 Rule, 68% of data falls within one standard deviation of the mean. Since 412.5 is one standard deviation above the mean (400 + 12.5), 16% of the data will be greater than 412.5 pounds per square inch (half of the remaining 32% outside the 68% range).