find the arithmetic mean of 12 observation 4,21,13,17,5,9,10,20,19,12,20,14 by assuming mean as 25. Also find mean by regular formula do you find differeence
Answers
How to solve average (arithmetic mean) word problems?
To solve various problems we need to follow the uses of the formula for calculating average (arithmetic mean)
Average = (Sums of the observations)/(Number of observations)
Follow the explanation to solve the word problems on arithmetic mean (average):
1. The heights of five runners are 160 cm, 137 cm, 149 cm, 153 cm and 161 cm respectively. Find the mean height per runner.
Solution:
Mean height = Sum of the heights of the runners/number of runners
= (160 + 137 + 149 + 153 + 161)/5 cm
= 760/5 cm
= 152 cm.
Hence, the mean height is 152 cm.
2. Find the mean of the first five prime numbers.
Solution:
The first five prime numbers are 2, 3, 5, 7 and 11.
Mean = Sum of the first five prime numbers/number of prime numbers
= (2 + 3 + 5 + 7 + 11)/5
= 28/5
= 5.6
Hence, their mean is 5.6
3. Find the mean of the first six multiples of 4.
Solution:
Calculated mean of 40 numbers = 38.
Therefore, calculated sum of these numbers = (38 × 40) = 1520.
Correct sum of these numbers
= [1520 - (wrong item) + (correct item)]
= (1520 - 36 + 56)
= 1540.
Therefore, the correct mean = 1540/40 = 38.5.
8. The mean of the heights of 6 boys is 152 cm. If the individual heights of five of them are 151 cm, 153 cm, 155 cm, 149 cm and 154 cm, find the height of the sixth boy.
Solution:
Mean height of 6 boys = 152 cm.
Sum of the heights of 6 boys = (152 × 6) = 912 cm
Sum of the heights of 5 boys = (151 + 153 + 155 + 149 + 154) cm = 762 cm.
Height of the sixth boy
= (sum of the heights of 6 boys) - (sum of the heights of 5 boys)
= (912 - 762) cm = 150 cm.
Hence, the height of the sixth girl is 150 cm.
Step-by-step explanation:
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