Answer:
Due to the higher z-score, Jane did better in class.
Step-by-step explanation:
Z-score:
In a set with mean and standard deviation , the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question:
Whoever's grade had the better z-score did better in class.
Mary's:
Mean of 85, standard deviation of 5, grade of 88. This means that . So
Jane's
Mean of 80, standard deviation of 10, grade of 88. This means that . So
Due to the higher z-score, Jane did better in class.
Variables are taken from the first letter of the color, ex: green = g.
Given:
r = g
2r = b = y
Total =42
So then:
r+ r + 2r + 2r = 42
6r = 42
r = 7
y = 2r
y = 2(7)
14 of the 42 pencils were yellow.
I really hope this helps. I’m sure the answer is c:)