The ages, in years, of 5 boys are 5, 6, 6, 8 and 10. Calculate, correct to one decimal place, the standard deviation of their ages.
Answer Details
To calculate the standard deviation, we need to follow these steps:
1. Find the mean (average) of the ages.
2. Find the difference between each age and the mean.
3. Square each of these differences.
4. Find the average of these squared differences.
5. Take the square root of this average.
Let's first find the mean of the ages:
mean = (5+6+6+8+10)/5 = 7 years
Now we can find the difference between each age and the mean:
|5 - 7| = 2
|6 - 7| = 1
|6 - 7| = 1
|8 - 7| = 1
|10 - 7| = 3
Next, we square each of these differences:
2^2 = 4
1^2 = 1
1^2 = 1
1^2 = 1
3^2 = 9
Now we find the average of these squared differences:
average = (4+1+1+1+9)/5 = 2.4
Finally, we take the square root of this average:
standard deviation = sqrt(2.4) ≈ 1.5
Therefore, the correct answer is not among the given options. The closest option is (d) 1.8 years, but this is not within one decimal place of the calculated standard deviation.