Ms.Smith has 28 sixth graders and 42 seventh graders for math. If she wants to break the two grades into identical groups withou
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Answer:
Q3 = 65.98 inches.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions 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.
Normally distributed with a mean of 64.9 inches and a standard deviation of 1.6 inches.
This means that
Find Q3, the third quartile that separates the bottom 75% from the top 25%.
This is X when Z has a pvalue of 0.75. So X when Z = 0.675.
Q3 = 65.98 inches.