frequency distributions

[Guest]

this is a novice question.... I can't get excel to figure out the
descriptive statistics for a simple survey. it goes like this.

The ages of newly hired, unskilled employees were grouped into the following
distribution:
18 to 21 4
21 to 24 8
24 to 27 11
27 to 30 20
30 to 33 7
I just want to figure out the median age! Help me please!!

 

[Biff]

Hi!

One way:

Entered using the key combination of CTRL,SHIFT,ENTER:

=MEDIAN(ROW(INDIRECT("18:33")))

Biff

 

[Mike Middleton]

craigw -

If you had the raw data, i.e., a list of the fifty ages, you could use
Excel's MEDIAN worksheet function.

But your data has already been summarized in a frequency distribution, so
you can only approximate the median.

(And, your frequency distribution is not well defined. If an employee is 21
years old, which interval was used?)

The median is the "middle-ranked value." If the employees were ranked from
youngest to oldest, the age of the 25th or 26th employee (or an age half way
in between) is the median.

For your frequency distribution, the median is in the "27 to 30" interval
(which includes ranks 24 through 43). Assuming the ages are uniformly
distributed in that interval, the median is slightly more than 27.
Statistics textbooks often have an interpolation formula for determining the
median from a frequency distribution.

Consult a textbook, or use Excel with the original raw data.

- Mike
www.mikemiddleton.com