Answer:
3. The number of copies he made is 1.25 standard deviations more than the mean number of copies made by teachers.
Step-by-step explanation:
In statistics, a z-score is measurement that describes a value's relationship to the mean and allows us to compare the value and the mean. It tells us how many standard deviations above or below the population mean.
Mr. Thomas has a z-score of 1.25.
He made 782 copies last week. The statistic this is being compared to is the mean of 550 copies by teachers per week at Lamley High School.
Therefore, the best interpretation is Mr. Thomas made 1.25 standard deviations more than the mean number of copies. The correct answer is <u>choice 3.</u>
Let's make sure the other choices are incorrect.
- The first answer is incorrect because a z-score doesn't compare the exact values, but uses the standard deviation to compare.
- The second answer is incorrect because he made 782 copies, while the mean was 550. He made <u>more</u> copies, plus the z-score is positive.
- The fourth and fifth answers are incorrect because the z-score doesn't use the median to compare.