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3 years ago

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CNNBC recently reported that the mean annual cost of auto insurance is 954 dollars. Assume the standard deviation is 234 dollars

. You take a simple random sample of 61 auto insurance policies. Find the probability that a single randomly selected value is at least 960 dollars.

1 answer:

timofeeve [1]3 years ago

7 0

Answer: 0.42

Step-by-step explanation:

Given: Mean : $\mu=954\text{ dollars}$

Standard deviation : $234\text{ dollars}$

Sample size : $n=61$

The formula to calculate z score is given by :-

$z=\dfrac{X-\mu}{\dfrac{\sigma}{\sqrt{n}}}$

For X=960

$z=\dfrac{960 -954}{\dfrac{234}{\sqrt{61}}}=0.200262812203\approx0.2$

The p-value = $P(X\geq960)=1-P(X$

Hence, the probability that a single randomly selected value is at least 960 dollars = 0.42

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