Measures of Center
To find the median, put all the numbers in order then cross off numbers until you find the middle.
To find the mean add them all then divide by how many numbers there are.
The mode is the number that appears the most.
What does the range tell you?
How spread out all of the numbers are in a data set.
Is this a statistical question?
"How many quarters are in a football game?
No
The dot plot shows the lengths of different boats in a race. How many boats were in the race?
11
Which has a greater MAD...
The number of miles driven in a day.
The number of miles walked in a day.
The number of miles driven in a day.
Find the mode in this data set:
10,12,8,11,13,9,2,1,9,12
The modes are 9 and 12.
What does the IQR tell you?
How spread out the middle 50% of the data values are.
Is this a statistical question?
"How long did you wait in line?"
Yes
The dotplot shows the lengths of boats in a race. Is there an outlier (if so, what is it)?
Yes, 28 feet.
Find the MAD of the data:
12,15,9,10,7,8,13,14
MAD=2.5
Find the median in this data set:
10,12,8,11,13,9,2,1,9,12
The median is 9.5.
Find the range in this data set:
23,33,25,16,27,43,29,40,35
The range is 24.
Is this a statistical question? If so, is it qualitative or quantitative?
"What night of the week do you watch your favorite show?"
Yes it is statistical. It is a qualitative question.
Make a dot plot from the table. Where is the peak?
24
Find the MAD of the data:
25,25,25,25,25
MAD=0
Find the mean in this data set:
10,12,8,11,13,9,2,1,9,12
The mean is 8.7.
Find Q1 and Q3 in this data set:
23,33,25,16,27,43,29,40,35
Q1=24 and Q3=37.5
Give an example of a statistical question.
Answers vary, but the question should be written so that a variety of answers are expected.
Make a dot plot from the table. Where is the cluster?
Around 24, between 22-27.
Is MAD a measure of center or variation?
Variation
Which is the best representation of this data? The mean, the median, or the mode?
67,71,74,78,88,89,91,99,99
Mean=84, Median=88, and Mode=99
The Mean is the best because the numbers on the left of the median are so spread out that the median is not a good representation of the data (one number is 21 points below the median, but it only goes as high as 11 points above the median).
Find the IQR in this data set:
23,33,25,16,27,43,29,40,35
The IQR is 13.5.
Design a statistical question that is qualitative. Then, tell how you could change the question to make in quantitative.
Answers vary.
Make a dot plot from the table. Where is the gap?
between 27-31.
5 shirt prices are $15, $21, $18, $19, $24
5 pants prices are $25, $32, $40, $36, $29
Find the MAD of each and compare.
The MAD for shirts is $2.48 and the MAD for pants is $4.48. The prices for shirts is more consistent (it doesn't change AS much).