What is a Mean ?
The arithmetic mean of a given data is the sum of all observations divided by the number of observations.
Mean = (Sum of all observations)/Number of observations
Problem 1 :
12.45, 12.99, 10.50, 11.25, 9.99, 12.72
Solution :
Mean = sum of all observations / number of observations
Here, n = 6
= (12.45 + 12.99 + 10.50 + 11.25 + 9.99 + 12.72) / 6
= (69.9) / 6
Mean = 11.65
Problem 2 :
28.8, 32.9, 32.5, 27.9, 30.4, 32.5, 31.6, 32.7
Solution :
Mean = sum of all observations / number of observations
Here, n = 8
= (28.8 + 32.9 + 32.5 + 27.9 + 30.4 + 32.5 + 31.6 + 32.7)
= (249.3) / 8
= 31.16
Problem 3 :
Four girls leaving a mall were asked how much money they had just spent. The amounts were $0, $14.95, $35.25, and $25.16. Find the mean amount of money spent.
Solution :
Mean = sum of all amount / number of girls
Here, n = 4
= (0 + 14.95 + 35.25 + 25.16) / 4
= 75.36 / 4
Mean = 18.84
She spent the money on average is $18.84.
Problem 4 :
Juan bought 5 shirts to wear to his new job. The costs of the shirts were $32.95, $38.50, $30.00, $17.45, and $24.25. Find the mean cost.
Solution :
Mean = sum of all shirt cost / number of shirts
Here, n = 5
= (32.95 + 38.50 + 30.00 + 17.45 + 24.25) / 5
= (143.15) / 5
= 28.63
The average cost is $28.63.
Problem 5 :
The number of minutes it took Jim to ride his bike to school for each of the past six days was 21, 18, 16, 19, 24 and 19. Find the mean number of minutes.
Solution :
Mean = sum of all days / total no of days
Here, n = 6
= (21 + 18 + 16 + 19 + 24 + 19) / 6
= (117)/6
= 19.5
The average number of minutes is 19.5.
Problem 6 :
Norris bought six books for his classes this semester. The costs of the books were $74.28, $120.95, $52.40, $10.59, $35.89, and $59.24. Find the mean cost.
Solution:
Mean = sum of all book cost / number of books
Here, n = 6
= (74.28 +120.95 + 52.40 + 10.59 + 35.89 + 59.24) / 6
=353.35 / 6
= 58.89
The average cost is $58.89.
Problem 7 :
The top eight hitters in a softball league have batting averages of .373, .360, .321, 321, .320, .312, .311, and .311. Find the mean of the batting averages. Round your answer to the nearest thousandth.
Solution :
Mean = sum of all batting averages / number of averages
Here, n = 8
= (.373 + .360 + .321, 321 + .320 + .312 + .311 + .311) / 8
= 2.629 / 8
= 0.328
The average of the batting is 0.338.
Problem 8 :
The monthly snowfall at a ski resort over a six-month period was 60.3, 79.7, 50.9, 28.0, 47.4, and 46.1 inches. Find the mean snowfall.
Solution :
Mean = sum of all period / number inches
Here, n = 6
= (60.3 + 79.7 + 50.9 + 28.0 + 47.4 + 46.1) / 6
= 312.4 / 6
= 52.06
The average of snowfall is 52.06 inches.
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