2.7 Measure of Central Tendency
Thursday, October 4, 2018
10:19 AM
Warm-up: Given the set -1, 6, -3, 0, -1, 4, 10, -2, -6, 2,
1. Write the numbers in order from least to greatest.
2. What number appears the MOST?
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MEAN, MEDIAN, MODE, RANGE
Data Set: 1, 6, -3, 0, -1, 4, 10, 2, 7, 2
MEAN: the average of a group or data
1) Add up all the data
2) Divide by the total number of data in the group
MEDIAN: the middle of a group or data
*If there is an odd number of data points, the number will be in the middle
*If there is an even number of data points, find the mean of the two middle
numbers
MODE: the number that occurs the MOST
RANGE: the difference between the largest data number and the smallest
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Data can be described by certain measures of central tendency. In general,
*If the numbers are evenly distributed (close together), use the ____________________ to
describe the data
*If the data is skewed (numbers are not close together), use the ____________________ to
describe the data.
*If the data contains no numbers, use the __________________ to describe the data.
Choose the best measure of central tendency.
1) Donations were collected for the sports fund. Amounts include:
$50, $110, $78, $81, $92, $60, $500, $58, $75
_____________________
2) Rylee scores the following points for her school's basketball game in the last 8 games:
16, 12, 12, 18, 14, 21, 20, 21
_____________________
3) Coach Bates was looking to order new jerseys for the baseball team. His players are
size S, M, L, L, M, XL, L, XL, M, L, S, L
_____________________
a) Mean?
b) Median?
4)
c) Mode?
d) Which is the best measure of
central tendency and why?
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 Solving an equation:
Suppose your grades on three math exams are 80, 93, and 91. What grade do you need on your
next exam to have a 90 average on the four exams?
Write and solve an equation to find the value of x
85, 87, 81, 92, 87, 80,x ; mean: 85
 Mean Absolute Deviation
Steps:
1. Find the mean.
-Add all the data values together and divide by how many there are.
2. Find the deviation from the mean.
-Subtract the mean from each data value.
3. Find the absolute deviation.
-Since distance cannot be negative, take the absolute value for the deviations found in step 2.
4. Find the Mean Absolute Deviation (MAD).
-Add all the absolute deviations and divide by how many there are.
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Thursday, May 30, 2019
10:20 AM
 Interquartile Range
CH 2.5-2.7 Page 4