The average number of pages in a novel is 326 with a standard deviation of 24
pages. If a sample of 50 novels is randomly chosen, what is the probability that
the average number of pages in these books is between 319 and 331?
Solution:
Given, "\\mu=326,\\sigma=24,n=50"
"X\\sim N(\\mu,\\sigma)"
"P(319\\le X\\le331)=P(\\dfrac{319-326}{24\/\\sqrt{50}}\\le z\\le\\dfrac{331-326}{24\/\\sqrt{50}})"
"=P(-0.04\\le z\\le0.03)=P(z\\le0.03)-P(z \\le-0.04)"
"=P(z\\le0.03)-[1-P(z \\le0.04)]=0.51197-[1-0.51595]\n\\\\=0.02792"
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