Median, Mode, and Range
The scores on Ms. Smiths most recent vocabulary test are shown below
80, 100, 85, 90, 90, 98, 81, 83, 87, 99, 72
What is the mode?
90
Find the mean of the set below
5, 10, 15, 15, 20, 35
20
In a box plot, we place vertical lines at the ______, _______, and ______
first quartile, median, third quartile
IQR stands for _________
Interquartile Range
Why do we use the median instead of the mode if there are outliers?
The outliers affect the mean, pulling it up or down, but the median stays unaffected.
The scores on Ms. Smiths most recent vocabulary test are shown below
80, 100, 85, 90, 90, 98, 81, 83, 87, 99, 72
What is the range?
18
Describe the steps to find the mean
Find the sum of scores. Then, divide the sum of scores by the number of scores
Find the median of the set below
4, 5, 6, 7, 8, 9, 10, 11
7.5
MAD stands for _________
Mean Absolute Deviation
75%, 80%, 85%, 88%, 78%, 83%, 89%
She decides to retake her topic 1 test and gets a 95%!
What will happen to her average?
The average or mean will go up!
YOU CHOOSE
Take away 200 points from the team of your choice, or gain 300 for your own team.
Find the median
20, 26, 15, 36, 32, 37
1) put in order
15, 20, 26, 32, 36, 37
The median is between 26 and 32
Median is 29
Lorri scores 75% 85% 85% and 95% on her math tests. What is her mean score?
85%
Find the first quartile of the set below
4, 5, 6, 7, 8, 9, 10, 11
4, 5, 6, 7, | 8, 9, 10, 11
4, 5, 6, 7
Q1= 5.5For the scores below, which measure would best describe the variability of the set
10, 10, 10, 11, 12, 12.5, 13, 34
Interquartile Range
34 is an outlier. This means that the mean is affected and so is the MAD
Ms. May found the following information about her class's final grades
Minimum: 75
First Quartile: 80
Second Quartile: 85
Third Quartile: 90
Maximum: 99
George's final grade was an 86%
That means that George's final score falls in
a) the bottom 25% of scores
b) the middle 50% of scores
c) the top 25% of scores
B
George' final score is within the interquartile range. That means he is in the middle 50%
Sum of scores divided by number of scores
24 divided by 8
3 points per game
Find the mean
4, 5, 6, 7, 8, 30
Mean: 10
Sum of scores: 60
60/6 = 10
Find the third quartile of the set below
1, 2, 3, 3, 4, 5, 6, 7, 8, 9, 10
8
For the scores below, which measure would best describe the variability? Then, find that measure
10, 15, 20, 25, 30
Mean Absolute Deviation
Mean: 20
Absolute Deviations: 10, 5, 0, 5, 10
MAD: 6
Find the mean absolute deviation of the scores below
8, 7, 15, 5, 11, 12, 19, 14, 5, 4
What is the mean absolute deviation?
*hint: the sum of scores is 100
Mean: 10
ADs: 2, 3, 5, 5, 1, 2, 9, 4, 5, 4,
MAD: 4
Rachel asked the kids in her class what types of pets they have. The responses are below
Rabbit: 5 students
Hamster: 2 students
Turtle: 1 studentFish: 12 students
Do we have enough information to find the mean and median and mode? Explain
We cannot find the mean and median because the scores are not numerical. We cannot add them and we cannot put them in order. We can find the mode based on which scores appear most often.
Challenge: What does the missing score need to be for the mean to be 12
____, 11, 13, 15,
This problem type will not be on your test
9
The sum of scores would have to be 48
48 divided by 4 = gives us a mean of 12
So the missing score needs to be 9
In the set below, the middle 50% of scores will fall between ________ and ________
1, 2, 3, 4, 4, 5, 6, 7, 8, 10
3 and 7
1, 2, 2, 2, 3, 4, 5, 5, 6, 16
Median
3.5
(median is between 3 and 4 which makes 3.5 the median)
CHALLENGE (This problem type will not be on your test)
Patrick has the following scores on his English tests
70, 70, 80, 90, ____
What will he need to receive on his final English test to have an 82% as his average?
Hint: There will be 5 scores. What would the sum of scores have to be?
100%