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Making a Line Plot. Collect data and put in chronological order. Ex. Scores on a math test 63 68 72 74 79 80 80 83 84 84 84 85 88 90 90 90 90 93 95 95 95 97. Determine a scale and intervals. - PowerPoint PPT Presentation
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Making a Line Plot
• Collect data and put in chronological order
• Determine a scale and intervals• If you have a small range, you should probably use intervals of 1
• With larger scales, it is best to mark intervals every 2, 5, or 10 numbers.
Ex. Scores on a math test
Use a scale from 60 to 100 and intervals of 5
Ex. Scores on a math test
63 68 72 74 79 80 80 83 84 84 84
85 88 90 90 90 90 93 95 95 95 97
Making a Line Plot
• Draw a horizontal line and mark the intervals
Ex. Scores on a math test
63 68 72 74 79 80 80 83 84 84 84
85 88 90 90 90 90 93 95 95 95 97
60 65 70 75 80 85 90 95 100
Making a Line Plot• Mark an X above the number for each data point• If a number is repeated, place one X above the
other Ex. Scores on a math test
63 68 72 74 79 80 80 83 84 84 84
85 88 90 90 90 90 93 95 95 95 97
60 65 70 75 80 85 90 95 100
X X X X XXX
X X X X
X X XXXX
X XX
X
Making a Line Plot• Count the number of data points and count the
number of X’s to make sure you plotted each point!
Ex. Scores on a math test
63 68 72 74 79 80 80 83 84 84 84
85 88 90 90 90 90 93 95 95 95 97
60 65 70 75 80 85 90 95 100
X X X X XXX
X X X X
X X XXXX
X XX
X
22 data points
22 X’s
Reading a Line Plot
• Understand the scale and intervalEx. This line plot has intervals of 2, so an X that falls between numbers would represent the median of those numbers.
An X between the 6 and 8 would represent “7”
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
Reading a Line Plot
Finding the Minimum
Minimum – smallest value
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
• The minimum is the number represented by the first X
1
Do NOT just look at the numbers on the scale. The Minimum is NOT 0
The MINIMUM is 1
Reading a Line Plot
Finding the Maximum
Maximum – greatest value
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
• The maximum is the number represented by the last X
15
Do NOT just look at the numbers on the scale. The Maximum is NOT 16
The MAXIMUM is 15
Reading a Line Plot
Finding the Range Range – difference between highest value and lowest value
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
• Subtract the number represented by the first X from the number represented by the last X
15 1
- = 14
Do NOT just look at the numbers on the scale. The Range is NOT 16 – 0 = 16
The RANGE is 14
Reading a Line Plot
Finding the MedianMedian – middle number when data is arranged in
chronological order
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
• Cross off the first and last X. Continue crossing off the first and last X’s until you reach the middle.
The MEDIAN is 8
Reading a Line Plot
Finding the MedianMedian – middle number when data is arranged in
chronological order
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
• If you get confused crossing off the X’s, list the numbers represented by the X’s in chronological order and cross them off.
1 2 4 4 7 8 8 8 10 10 10 11 15
Reading a Line Plot
Finding the MedianMedian – middle number when data is arranged in
chronological order
0 2 4 6 8 10 12 14 16
X X XX
X X X XXX
X X
• If there are 2 numbers left in the middle, the median is the middle of those 2 numbers.
The 2 middle numbers are 7 and 8, so the median is 7.5
Reading a Line Plot
Finding the ModeMode = Most often
0 2 4 6 8 10 12 14 16
X X XX
X XX
XXX
X X
Reading a Line Plot
Finding the MeanMean – average
0 2 4 6 8 10 12 14 16
X X XX
X XXX
XXX
X X
• Add all the data points and divide by the total number of data points
• Remember to include ALL the X’s
1
Continue for all data points
2 4 4 7
+ + + + + 8 + 8 + 8 + 10 + 10 + 10 + 11 + 15
Add Them Up!
98
Divide by the
# of X’s 13 X’s so divide by 13 ÷ 13 ≈
7.538Round if you get a long decimal
≈ 7.5
The MEAN is 7.5
