Inga, Kai, and Jason volunteer in the school library. They want to find the average number of pages of a library book. It would be unreasonable to calculate the number of pages in every book to find the average. They decide they need to find a valid sample. Inga suggests choosing 100 books from the history section to get a sample.

Kai suggests randomly selecting 100 books from the library’s entire catalog.

Jason suggests using 100 books from the teen fiction section to get a sample.

Who suggested the best way to produce a random sample that is not biased?

suggested the best way to produce a random sample that is not biased.

what is the model?

step-by-step explanation:

im not sure what this means: mc011-7.jpg

step-by-step explanation:

irst, find the z score of a score of 80. this is given by the formula z = (x-u)/o, where x is the score, u is the mean, and o is the standard deviation. this gives

z = (80-78)/12 = 1/6 = .1667

now, find what percentile a z score of 1/6 correlates to in the normal distribution.

a z score of 1/6 = .1667 is equivalent to the 56.36th percentile of the distribution. so the probability a score is over this is 1-.5636 = .4364

the mean of a sample mean is equal to the original mean. however, the standard deviation of a sample mean is equal to the original standard deviation divided by the square root of n (sample size). so the new standard deviation is 12/sqrt(16) = 3.

the new z score is 80-78/3 = 2/3 = .667. this is equivalent to the 74.86th percentile. so the probability that the mean will be greater than this score is 1-.7486 = .2514.

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