Answer:
10.20% probability that a randomly chosen book is more than 20.2 mm thick
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
250 sheets, each sheet has mean 0.08 mm and standard deviation 0.01 mm.
So for the book.
What is the probability that a randomly chosen book is more than 20.2 mm thick (not including the covers)
This is 1 subtracted by the pvalue of Z when X = 20.2. So
has a pvalue of 0.8980
1 - 0.8980 = 0.1020
10.20% probability that a randomly chosen book is more than 20.2 mm thick