Expert: Vivian - 5/23/2008

Question
For 75 employees of a large department store, the following distribution for years of service was obtained.  How can I construct a histogram, a frequency polygram and ogive, for the data?

class limits             frequency
1-5                        21
6-10                       25
11-15                      15
16-20                       0
21-25                       8
26-30                       6

A majority of the employees have worked for how many years or less?


This is not a homework question!!!!!  

Answer
Histogram(bars): please read the definition and examples at http://en.wikipedia.org/wiki/Histogram
You may draw it by hand or by excel.

Frequency polygram (lines instead of bars); In statistics, an ogive is the curve of a cumulative distribution function. Build the ogive based on the following function:
Y=21/75 if 1<=x<6, (21+25)/75 if 6<=x<11, (21+25+15)/75 if 11<=x<21, (21+25+15+8)/75 if 21<=x<26, 1 if 30>x>=26.

The ogive will look like the first curve at
http://en.wikipedia.org/wiki/Image:Discrete_probability_distribution_illustratio...

A majority of the employees have worked for how many years or less?
75*0.5=37.5
A majority of the employees have worked for 10 years or less.