Math 10 - What Is a Histogram

IB Math SL – year 2 - What is a histogram?

The histogram is a ______showing a count of how the data points fall in various ranges. A histogram is used when the data to be represented is ______.

The groups of data are called ______or ______, because one can think of them as containers that hold the data and get "filled up." A frequency table, which shows ______a test score occurred, helps us draw a histogram.

Consider the exam scores of a group of students.

Frequency Table – Test Scores for Reid’s ACS 11

Group (or Bin or Class) Count 0 – <10 1 10 – <20 2 20 – <30 3 30 – <40 4 40 – <50 5 50 – <60 4 60 – <70 3 70 – <80 2 80 – <90 2 90 - 100 1

Histogram – Test Scores for Reid’s ACS 11 To ______the histogram, bins are plotted on the x axis and their ______on the y axis. At left is a histogram for the frequency table above. The bars of a histogram must touch each other –

no ______in between.

A bar or ______graph is similar to a histogram, except that the data is ______. This fact is indicated on the graph by using ______between the bars:

Spaces (x 2) Bins Construct Column Frequencies Chart Classes Discrete Included How often Continuous Create a histogram to create one for this data:

The following data represents the number of games each of CP Allen’s sports teams won this year: 7, 15, 24, 4, 4, 29, 36, 4, 7, 6, 18, 25, 32, 17, 5, 4, 28, 30, 35

Range and number of bins Tally and frequency chart

Number of teams (frequency)

Number of games won

Frequency Polygon - CP Allen Sports team performance

6 What about a frequency polygon? 5 s m

A frequency polygon is almost the same thing as a e t

f o histogram: you still do a tally chart, and create a graph. 3 r e However, instead of drawing bars, you place dots in the b m 2 u

middle of each bin and then connect the dots with a line: N 1

0 0 6 12 18 24 30 36 Number of games won

What is obvious from a histogram: What is not obvious on a histogram  The distribution (spread) of the data  The mean  The range (lowest to highest)  The median  The class/bin where the mode falls (the  If there were any outliers modal class)  How many data points there were in total (not including outliers)