A researcher for a travel company is looking into the prices people are willing to pay for airplane tickets. The company has communicated that the overall population mean is $265 with a standard deviation of $40.93. The researcher has a sample of 130 ticket purchases from one location. By the central limit theorem, which interval can the researcher be 95% certain that the sample mean will fall within? A.
$261.41 and $268.59
B.
$257.82 and $272.18
C.
$264.37 and $265.63
D.
$254.23 and $275.77

just took the test and my answers down below!

step-by-step explanation:

check the pic :

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."