Question 1182711: CNNBC recently reported that the mean annual cost of auto insurance is 1046 dollars.
Assume the standard deviation is 221 dollars, and the cost is normally distributed.
You take a simple random sample of 37 auto insurance policies.
Round your answers to 4 decimal places.
a. What is the distribution of X?
X-N(1046,221)
b. What is the distribution of x?
x-N(1046,___________)
c. What is the probability that one randomly selected auto insurance is less than $1050?
d. A simple random sample of 37 auto insurance policies, find the probability that the average cost is less than $1050.
0.5438
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website!
a. ~N(1046, 221^2)
b. ~N(1046, 221^2/37); the sd of the sampling distribution is the original sd/sqrt(n)
c. z < (1050-1046)/221/sqrt(37)
z<+.11
probability is 0.5438
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