Download Name__________________ Date 12/19 GPAs of a college

Name__________________
Date 12/19
1. GPAs of a college freshman class have approximately the normal distribution with mean
2.87 and standard deviation .34.
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a. Sketch the graph of the normal distribution out to 3 standard deviations.
b. What percentage of freshmen have a GPA above 3.21?
c. What percentage of freshmen have a GPA between 2.87 and 3.55?
d. If this specific college puts freshmen on an improvement plan that score below 2
standard deviations of the mean, what percentage of freshmen would be on the
improvement plan?
2. The length of elephant pregnancies from conception to birth varies according to a
distribution that is approximately normal with mean 525 days and standard deviation 32
days.
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a. Sketch the graph of the normal distribution out to 3 standard deviations.
b. What percent of pregnancies last more than 589 days?
c. What percent of pregnancies last between 493 and 589 days?
d. 99.7% of pregnancies will be between how many days?
3. Wingspans of adult herons have approximate normal distribution with mean 125 cm and
standard deviation 12 cm.
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a. Sketch the graph of the normal distribution out to 3 standard deviations.
b. What percentages of herons have wingspan more than 101 cm?
c. What percentages of herons have wingspan less than 113 cm?
d. What percentile would a heron be with a wingspan of 137?
4. When robins’ eggs are weighed, it turns out that they vary according to approximately the
normal distribution with mean 17.5 mg and standard deviation 3.5 mg.
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a. Sketch the graph of the normal distribution out to 3 standard deviations.
b. What percentage of robins’ eggs weigh between 7 mg and 21 mg?
c. What percentage of robins’ eggs weigh between 14 mg and 21 mg?