Mathematics
Grade 7
15 min
Changes in mean, median, mode, and range
Changes in mean, median, mode, and range
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1
Introduction & Learning Objectives
Learning Objectives
Define and calculate mean, median, mode, and range for a given data set.
Predict how adding a new data point affects the mean, median, mode, and range.
Predict how removing an existing data point affects the mean, median, mode, and range.
Analyze how changing an existing data point affects the mean, median, mode, and range.
Explain the impact of outliers on measures of central tendency and spread.
Apply their understanding to interpret changes in real-world data scenarios.
Ever wonder how a new player's score or a sudden sale affects a team's average or a store's typical price? 📊 Let's explore how data changes!
In this lesson, you'll learn what happens to the mean, median, mode, and range of a data set when numbers are added, re...
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Key Concepts & Vocabulary
TermDefinitionExample
Data SetA collection of numbers or values related to a particular subject.The ages of students in a club: {12, 13, 12, 14, 13}
MeanThe average of a data set, found by summing all values and dividing by the number of values.For {2, 4, 6}, the mean is (2+4+6)/3 = 12/3 = 4.
MedianThe middle value in a data set when the values are arranged in order. If there are two middle values, the median is their average.For {2, 3, 5, 8, 9}, the median is 5. For {2, 3, 5, 8}, the median is (3+5)/2 = 4.
ModeThe value that appears most frequently in a data set. A data set can have one mode, multiple modes, or no mode.For {1, 2, 2, 3, 4}, the mode is 2. For {1, 1, 2, 2, 3}, the modes are 1 and 2.
RangeThe difference between the highest and lowest values in a data set. It measures the sp...
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Core Formulas
Calculating the Mean
$ ext{Mean} = \frac{\text{Sum of all data values}}{\text{Number of data values}}$
To find the average, add up all the numbers and then divide by how many numbers there are. When data changes, either the sum or the count (or both) will change, requiring recalculation.
Finding the Median
1. Order the data from least to greatest. 2. Find the middle value. If there's an odd number of values, it's the single middle number. If there's an even number, it's the average of the two middle numbers.
When data is added or removed, the order of the data set might change, and the position of the middle value(s) will definitely change, requiring reordering and re-identifying the median.
Identifying the Mode
The mode is the value that appears mo...
5 more steps in this tutorial
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Challenging
A data set of 5 numbers has a mean of 20 and a median of 22. A new number is added to the set, making the new mean 21. What was the number added?
A.20
B.21
C.26
D.28
Challenging
A student has three test scores: 80, 85, and 95. What score must the student get on the fourth test so that the mean and the median of the four scores are equal?
A.85
B.90
C.95
D.100
Challenging
A data set consists of 5 distinct integers with a range of 10 and a median of 15. If the mean is 14, what happens to the mean if the highest value is increased by 5?
A.It increases by 1.
B.It increases by 5.
C.It stays the same.
D.It cannot be determined.
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