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1 answer:
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Answer:
a) 6.68% of heights less than 150 centimeters
b) 58.65% of heights between 160 centimeters and 180 centimeters
Step-by-step explanation:
When the distribution is normal, we use 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, we have that:
a) The percentage of heights less than 150 centimeters
We have to find the pvalue of Z when X = 150. So
has a pvalue of 0.0668
6.68% of heights less than 150 centimeters
b) The percentage of heights between 160 centimeters and 180 centimeters
We have to find the pvalue of Z when X = 180 subtracted by the pvalue of Z when X = 160.
X = 180
has a pvalue of 0.9878
X = 160
has a pvalue of 0.4013
0.9878 - 0.4013 = 0.5865
58.65% of heights between 160 centimeters and 180 centimeters