The mean annual cost of car insurance is $939. The standard deviation is $300. You have been asked to compute the probability that a simple random sample of car insurance policies of size 100 will have a sample mean within $25 of the population mean.
calculate the standard deviation of x-bar?
a. $300
b. $3
c. $1.73
d. $5.48
e. $30
please show work
calculate the standard deviation of x-bar?
a. $300
b. $3
c. $1.73
d. $5.48
e. $30
please show work
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The standard deviation of x-bar is the population standard deviation ($300) divided by the square root of the sample size. The sample size is 100, so its square root is 10. $300/10 = $30.
Answer is e.
Answer is e.