Question

Lisa has collected data to find that the number of pages per book on a book shelf has a normal distribution. What is the probability that a randomly selected book has less than 168 pages if the mean is 192 pages and the standard deviation is 24 pages? Use the empirical rule. Enter your answer as a percent rounded to two decimal places if necessary.

Answer 1

The answer is "Thus a chosen random book has a 15.87% chance of fewer than 170 pages".

Explanation:

`Mean = 190\\\\\text{Standard devaition} \ \sigma= 20\\\\\to P(\bar{x}<70)\\\\Z = ((170-190))/(20)`

`= (-20)/(20) \\\\=-1`

It found a p-value from its empirical rule:

`\to P(\bar{x}<170) = 0.1587`