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a researcher wishes to estimate within $300 the true average amount of money a county spends on road repairs each year. if she wants to be 90% confident, how large a sample is necessary? the standard deviation is known to be $900.

Answer :

The sample size should be 24.

What is the sample size?

The process of deciding how many observations or replicates to include in a statistical sample is known as sample size determination. Any empirical study with the aim of drawing conclusions about a population from a sample must take into account the sample size as a crucial component.

Here, we have

Given

Margin of error = 300

confidence level = 0.9

standard deviation = 900

Assuming the standard deviation to be of population

ME = Z(0.1/2) × σ/√n

300 = 1.645 × 900/√n

n =  {(1.645 × 900)300}²

n = 24

Hence, the sample size should be 24.

To learn more about the sample size from the given link

https://brainly.com/question/24158610

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