To calculate the standard deviation of a set of scores, we follow these steps:
- Find the mean (average) of the scores:
- Add all the scores together: 5 + 4 + 6 + 7 + 8 = 30.
- Divide the total by the number of scores: 30 ÷ 5 = 6.
Therefore, the mean is 6.
- Calculate the squared differences from the mean:
- For each score, subtract the mean and then square the result:
- (5 - 6)² = 1
- (4 - 6)² = 4
- (6 - 6)² = 0
- (7 - 6)² = 1
- (8 - 6)² = 4
- Find the average of these squared differences:
- Add the squared differences together: 1 + 4 + 0 + 1 + 4 = 10.
- Divide by the number of scores: 10 ÷ 5 = 2.
This result is the variance, which is 2.
- Take the square root of the variance to get the standard deviation:
The standard deviation of the scores 5, 4, 6, 7, and 8 is therefore √2, which is approximately 1.41, but following the options provided, the answer matches with √2.