Question

The monthly rents (in dollars) paid by 9 people are given below.

(Note that these are already ordered from least to greatest.)
755, 855, 970, 985, 990, 1010, 1020, 1060, 1085
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Suppose that one of the people moves. Her rent changes from $1085 to $995.
Answer the following.
(a) What happens to the median?
it decrease by __?
it increase by__?
it stays the same
(b) What happens to the mean?
It increases by __?
It stays the same
it decreases by__

Answer 1

Explanation:

the median just identifies the value, where half of the other values are smaller, and the other half of the other values are bigger.

in the original set this is 990.

by changing 1085 to 995 this value still stays on the bigger side of 990, so the median is still 990 and unchanged.

the mean changes.

the mean is the sum of all values divided by the number of values.

originally it was

(755+855+970+985+990+1010+1020+1060+1085)/9 = 970

now it is

(755+855+970+985+990+995+1010+1020+1060)/9 = 960

it decreased by 10.