that we have access to an entire population, or that we are discussing a distribution, we use the statistics
rather than parameters.)
example: During his major league career, Babe Ruth hit the following number of home runs
(1914–1935): 0, 4, 3, 2, 11, 29, 54, 59, 35, 41, 46, 25, 47, 60, 54, 46, 49, 46, 41, 34, 22, 6.
What was the mean number of home runs per year for his major league career?Calculator Tip: You should use a calculator to do examples like the above—it’s a waste of time to do
it by hand, or even to use a calculator to add up the numbers and divide by n . To use the TI-83/84,
press STAT ; select EDIT ; enter the data in a list, say L1 (you can clear the list, if needed, by moving
the cursor on top of the L1 , pressing CLEAR and ENTER ). Once the data are in L1 , press STAT , select
CALC , select 1-Var Stats and press ENTER. 1-Var Stats will appear on the home screen followed
by a blinking cursor — the calculator wants to know where your data are. Enter L1 (It’s above the 1;
enter 2ND 1 to get it). The calculator will return x ̄ and a lot more. Note that, if you fail to enter a list
name after 1-Var Stats (that is, you press ENTER at this point), the calculator will assume you mean
L1 . It’s a good idea to get used to entering the list name where you’ve put your data, even if it is L1 .Median
The median of an ordered dataset is the “middle” value in the set. If the dataset has an odd number of
values, the median is a member of the set and is the middle value. If there are 3 values, the median is the
second value. If there are 5, it is the third, etc. If the dataset has an even number of values, the median is
the mean of the two middle numbers. If there are 4 values, the median is the mean of the second and third
values. In general, if there are n values
in the ordered dataset, the median is at the position. If you have 28 terms in order, you will find the
median at the position (that is, between the 14th and 15th terms). Be careful not to interpret
as the value of the median rather than as the location of the median.example: Consider once again the data in the previous example from Babe Ruth’s career. What
was the median number of home runs per year he hit during his major league career?
solution: First, put the numbers in order from smallest to largest: 0, 2, 3, 4, 6, 11, 22, 25, 29, 34,
35, 41, 41, 46, 46, 46, 47, 49, 54, 54, 59, 60. There are 22 scores, so the median is found at the
11.5th position, between the 11th and 12th scores (35 and 41). So the median is