Answer:
# yellow = 20
# blue = 23
# red = 5
Step-by-step explanation:
let 'r' = # red marbles
let '4r' = # yellow marbles
let '3+4r' = # blue marbles
r + 4r + 3 + 4r = 48
9r + 3 = 48
9r = 45
r = 5
red = 5
yellow = 4(5) = 20
blue = 3+4(5) = 23
Answer:
The score that separates the lower 5% of the class from the rest of the class is 55.6.
Step-by-step explanation:
Problems of normally distributed samples can be solved using the z-score formula.
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:

Find the score that separates the lower 5% of the class from the rest of the class.
This score is the 5th percentile, which is X when Z has a pvalue of 0.05. So it is X when Z = -1.645.


The score that separates the lower 5% of the class from the rest of the class is 55.6.