Question

STATISTICS PLEASE HELP

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 between 375 and 425 pounds per square inch?


a. 32%

b. 84%

c. 95%

d. 68%

e. 47.5%


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Answer 1

95

Explanation:

If the mean is 400 and the standard deviation 12.5. It means that a range between 375 and 425 is the mean +- 2 standard deviations

400 - 12.5*2 = 375

400 + 12.5*2 = 425

Which means the probability is 95%

When you are looking for +- 1 deviation standard the probability is 68, and for +- 3 the probability is 99.7

There is a more complex explanation based on Z, but assuming you are only applying 68-95-99.7 rule this should be enough.