6.15. Median. Mean. Mode. Click the happy face to see a power point by Jennifer Del-Castillo of JFKM. Control/Click the link to play a practice game http://www.kidsmathgamesonline.com/numbers/meanmedianmode.html. This is the stuff you will need to be able to do. Easy!!.
to be able to do
Find the mean for a set of data.
Describe the three measures of center and a situation in which each would best represent a set of data.
3. Identify and draw a number line that demonstrates the concept of mean as balance point for a set of data.
Not quite as easy
Different, but not so hard
Mean –The sum of the numbers in a set of data divided by the number of pieces of data.
EX- grades averaged: 2, 6, 7, 7, 10
Add them up= 32
Divide by how many numbers are in the data set 32/5 = 6.4
Synonyms are Fair Share, Average, Balance Point
The number(s) or item(s) that appear most
often in a set of data.
EX- 85, 92, 100, 100, 91, 86, 78
The Mode is 100.
If there are exactly two modes the data set is
The middle number in a set of data when arranged in numerical order.
Think of the median of the road, right in the middle.
EX Odd Set- 85, 72, 100
arrange 72, 85, 100
The median is 85.
Ex Even Set- 85, 92, 100, 105
The median is the average of 92 and 100.
92 + 100= 192 divide by 2 and the Median is 96.
Information, often numerical, which is gathered for statistical purposes.
EX- Grades for a 9 weeks
The difference between the greatest number and the least number in a set of data.
EX- 2, 9, 6, 8
Place in numerical order 2,6,8, 9
Subtract smallest number from greatest number 9-2
Range = 7
A number that helps describe all of the data in a data set.
Ex- Mean, Mode, Median, Range
A number that is numerically distant from the rest of the data
If students scored a 100, 89, 92, 79, and 23,
23 is Way Off from the other scores. 23 is the outlier.
Measure of Central Tendency?
Mean works well for sets of data with no very high or low numbers.
Median is a good when data sets have a couple of values much higher or lower than most of the others.
Mode is a good to use when the data has some identical values or when working with data in a yes or no survey.
Mean can be defined as the point on a number line where the data distribution is balanced.
This is the concept of mean as the balance point.
This seesaw is NOT balanced!
Now think of a number line as a line plot. The fulcrum (triangle) is the mean.
Here the mean is 12.
We have been given three plotted points. But to balance, we need to have two points on each side of the line plot!
So how do you figure that out!
First, draw a line up through 12
Next, count how far apart the plotted numbers are from 12 on each side. Plot corresponding circles on each side to balance!
The numbers 7,9, 15,and 17 have a mean of 12!
What is the missing point?
What is the missing point?
be asked to answer for
the balance point, or mean.
There will be counters on a number line. Each counters represents a unit of the number it is sitting at. 1 x 4= 4 2 x 6 = 12 and so on.
What you will be asked to do is jump the counters to find the mean. You start at the outside edges. Click to see.
or mean, is 7
to try on your own!
Before we start
make sure you have
this in your notebook….
Move the outside counters from each side towards the center to meet the balance point