Parameters are
a. numerical characteristics of a population
b. the averages taken from a sample
c. numerical characteristics of a sample
d. numerical characteristics of either a sample or a population

a. numerical characteristics of a population

Step-by-step explanation:

Parameters and Statistics

It's important to mention that there is a difference between parameters and statistics.

A statistic is a numerical value of a variable that is part of a sample of the population. We have for example the sample mean or the sample standard deviation s as examples of statistics.

A parameter is a value who represent a numerical characteristic of a population. We have for example the population mean or the population standard deviation as examples of parameters.

Based on this the best answer would be:

a. numerical characteristics of a population

the answer would be 150 books

step-by-step explanation:

if you divide 300 by 2 you will get 150

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