12.2.1 Measures of Central Tendencies, PT3 Focus Practice


12.2.1 Measures of Central Tendencies, PT3 Focus Practice
 
Question 1:
Given that the mode of the set of data 7, 5, 3, 2, 3, y, 7, 6 and 5 is 7, find the mean.

Solution:
If the mode is 7, then y = 7
Mean = 7 + 5 + 3 + 2 + 3 + 7 + 7 + 6 + 5 9 = 45 9 = 5


Question 2:
The mean of the set of numbers 7, 2, x, 4, 5, 3, y is 5. The value of x + y is

Solution:
Mean = sum of all values of data total number of data 7 + 2 + x + 4 + 5 + 3 + y 7 = 5 x + y + 21 = 7 × 5 x + y = 35 21 x + y = 14


Question 3:
Table below shows the number of story books read by a group of pupils in a week.

Number of books
1
2
3
4
5
Number of pupils
3
0
1
5
6
The median of the data is

Solution:

Number of books
1
2
3
4
5
Number of pupils
3
0
1
5
6
Position
1 – 3
3
4
5 – 9
10 – 15
Number of pupils = 3 + 0 + 1 + 5 + 6 = 15
Middle position situated at 8th.
From the table, the position 8 has a value of 4, therefore the median of the data is 4.

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