QUESTION Porcelain tile is often recommended over ceramic tile because its break
ID: 2928135 • Letter: Q
Question
QUESTION Porcelain tile is often recommended over ceramic tile because its breaking strength tends to be higher therefore making it more durable and long lasting. Based ordata collected from its production processes, Crosstiles Inc. determines that the 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. 1. breaking strength of its 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. Approximately 20% B. Approximately 32% C. Approximately 1.3% D. Approximately 16% QUESTION 9 At a local manufacturing plant, employees must complete new machine set ups within 30 minutes. New machine set-up times can be described by a normal model with a mean of 22 minutes and a standard deviation of four minutes. 1. What percent of new machine set ups take more than 30 minutes? A. Approximately 97.72% B. Approximately 95% C. Approximately 99.7% D. Approximately 2.28% QUESTION 10 At a local manufacturing plant, employees must complete new machine set ups within 30 minutes. New machine set-up times can be described by a normal model with a mean of 1. 22 minutes and a standard deviation of four minutes. The typical worker needs five minutes to adjust to their surroundings before beginning their duties. What percent of new machine set ups are completed in less than 25 minutes? A. Approximately 68% B. Approximately 77.3% C. Approximately 22.7% D. Approximately 25%Explanation / Answer
8) for it lies at one std deviation whcih is at 84th percentile ; therefore above it 16% remains.
option D
9)for 30 minutes are 2 std deviation above mean
hence option D
10)
for P(X<25) =P(Z<(25-22)/4)=P(Z<0.75)=77.3%
therefore optioin B os correct.