Answer :
Final answer:
To determine if a score is 'unusual' in a normally distributed set of scores, we look if it's within one standard deviation from the mean. In this case, any scores outside the range of 56 to 90 could be considered unusual. Therefore, the scores 37.5 and 39.3 are considered unusual.
Explanation:
The student's question refers to the concept of standard deviations in Statistics, which is a measure of how spread out numbers in a data set are. In a normal distribution of scores, most scores fall within one standard deviation from the mean (average). So scores that fall outside of this range can be considered as 'unusual'.
The standard deviation for the Calculus test is 17 and the mean is 73. So, any score below (73 - 17 = 56) or above (73 + 17 = 90) could be considered unusual.
With this in mind, the unusual scores from the options provided are: a. a score of 37.5 and e. a score of 39.3, as they fall well below 56.
Learn more about Standard Deviations here:
https://brainly.com/question/34623630
#SPJ11