


12062012, 12:47 PM


Groupie


Join Date: Dec 2011
Posts: 1,325
SoCal
High School English


Math question, mean/median/mode
I'm trying to analyze data for one of my classes. I've isolated 21 students as a specific subgroup. I want to know the mode. There are 3 different scores that are each repeated 4 times. What is the mode? The average of those 3 scores?
My scores out of 15:
5
5
5
7
7
7
7
8
8
9
9
11
11
11
11
12
12
12
12
13
14
Is the mode 10? Is the mean 9?

12062012, 01:12 PM


Groupie


Join Date: Dec 2011
Posts: 1,325
SoCal
High School English


How do you figure out the mode if you have one of each number?
6
7
8
12
13
14

12062012, 01:15 PM


Cohort


Join Date: May 2011
Posts: 593
California
4th Grade Teacher


The mode is the most frequent number seen in a set of data. If they are all equal, you would have no mode. If there are two numbers (let's say) that you see the most of, then you have two modes.

12062012, 01:34 PM


Groupie


Join Date: Dec 2011
Posts: 1,325
SoCal
High School English


No mode? Two modes? How would I illustrate that on a chart? See this is what happens when English teachers try to teach math. My professor said to take the average of them. Or maybe she said that about the median.

12062012, 02:11 PM


Cohort


Join Date: Mar 2011
Posts: 596
Adjacent To Your House
HS Senior


The mode is supposed to be the number that appears the most. I was always told you can have more than one mode. Yes, but there could definitely be no mode.

12062012, 02:13 PM

Cohort


Join Date: Oct 2007
Posts: 742
Canada


Quote:
Originally Posted by HeartDrama
No mode? Two modes? How would I illustrate that on a chart? See this is what happens when English teachers try to teach math. My professor said to take the average of them. Or maybe she said that about the median.

If you have two numbers in the middle of a data set, you calculate the average of the two numbers as the median. If you have 4 numbers repeated the same amount of times in a data set, you have 4 modes.

12062012, 02:14 PM


Cohort


Join Date: Mar 2011
Posts: 596
Adjacent To Your House
HS Senior


The mean is the average so you would add those up get a number and divide by how many numbers you added together.

12062012, 02:15 PM

Multitudinous


Join Date: May 2005
Posts: 25,449
Calif.


The mode isn't the average of anything, no: it's the score that appears most often in the data set, and you can indeed have more than one of them.
You have a trimodal distribution here, with four 7's, four 11's, and four 12's  though for the relatively small number of data points you've got here, identifying that many modes is kind of silly; I'd be inclined to put an asterisk in the chart where the mode is supposed to go and explain it below.
When all the numbers are unique or all tie, you've got no mode; fill that space on the chart with an asterisk if you feel like explaining below or "N/A" if you don't. Anyone who understands the concept should know what is intended; anyone who demands that there must be a mode doesn't understand the concept.
Average and mean are the same thing: sum up the scores and divide by the number of scores. In this case, 196/21 = 9.33.
9 is the median here: the middlemost number, if you will.
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12062012, 04:09 PM


Moderator


Join Date: Aug 2002
Posts: 15,527
Florida


And remember that the median is the middle when the data is recorded in ascending or descending order.

12062012, 04:27 PM

Multitudinous


Join Date: May 2005
Posts: 25,449
Calif.


I did take the ordering of the data for granted, didn't I, 'daisy? (Bad TG: no shortbread.)
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