Lesson 10: Averages.
Mathswatch 41/133
GCSE Maths Starter 10
1) Find the median and the
range in the stem and leaf
below.
2. Write 56 as a product of
its prime factors.
3. Simplify (y⁵)³
4. Solve 4(x + 7) = 36
5. Describe fully the single
transformation that
maps A onto B.
Lesson 10: Averages.
Mathswatch 41/133
• To calculate the mean, median, mode and
range from a list of data.
• To estimate the median and modal group from
grouped data.
• To estimate the mean from data in a table.
EXTN: To solve problems involving mean from a
table when the table isn’t drawn for you.(Grade
C)
Lesson 10: Averages.
Mathswatch 41/133
Play this youtube clip:
http://www.youtube.com/watch?v=z
zDDUc_yP2I
Lesson 10: Averages.
Mathswatch 41/133
So… Most Common
• If we know:
• The Mode = Most Common
• What is the mode average of the following numbers?
2, 6, 4, 2, 5, 8, 7, 4, 2, 6, 3, 2, 2, 3
Lesson 10: Averages.
Mathswatch 41/133
So… Median = Middle
• You need to put the numbers in order; from
the lowest to the highest
• And find the
halfway point:
2, 6, 4, 2, 5, 8, 7, 4, 2, 6, 3, 2, 2, 3
Lesson 10: Averages.
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The
Mean
• Think of a mean old man counting out his
money!
• He adds all of the values together and divides
the total by the number of values he has.
Lesson 10: Averages.
Mathswatch 41/133
So… calculation of the mean
• Add together the numbers:
2+6+4+2+5+8+7+4+2+6+3+2+2+3
=?
And divide by the total by the number of values
you have
56
14
=4
Lesson 10: Averages.
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The
Range
• Take the highest value and subtract the lowest
value:
2, 2, 2, 2, 2, 3, 3, 4, 4, 5, 6, 6, 7, 8
Answer: 8 – 2 = 6
Lesson 10: Averages.
Mathswatch 41/133
For averages from a table Watch Mathswatch clip 133.
Mathswatch Website
Centre ID: bbs
Login: burton
Password: radius
Lesson 10: Averages.
Mathswatch 41/133
30
MP
MP x Freq
5
2 x 5 = 10
15
120
25
225
35
245
45
180
780
Often it tells
you what to
divide by in
the first
sentence
÷ 30 = 26
Lesson 10: Averages.
Mathswatch 41/133
• To calculate the mean, median, mode and
range from a list of data.
• To estimate the median and modal group from
grouped data.
• To estimate the mean from data in a table.
EXTN: To solve problems involving mean from a
table when the table isn’t drawn for you.(Grade
C)