It is known that student A and student B have the same average score for jumping rope in 1 minute. If the variance of student A's 1-minute jumping rope score is , and the variance of student B's 1-minute jumping rope score is , then which of the following is true?
Pick one
Solution
Given that student A and student B have the same average score for jumping rope in 1 minute, we compare their score stability by looking at their variances. The variance measures the spread of the scores around the mean; a lower variance indicates that the scores are more tightly clustered around the mean, implying greater stability.
- The variance of student A's 1-minute jumping rope score is given as .
- The variance of student B's 1-minute jumping rope score is given as .
To determine which student's score is more stable, we compare the variances:
Since a lower variance indicates greater stability, and , it follows that student A's score is more stable than student B's score.
Therefore, the correct answer is .
Want a route through all this instead of an archive? The track
puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.