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What Percentage Of Compounds Formed From The Extract Of This Plant Fall Within 2 Standard Deviations Of The Me?

PostPosted: Wed Oct 11, 2017 6:51 am
by Soren
The extract of a plant native to Taiwan has been tested as a possible treatment for Leukemia. One of the chemical compounds produced from the plant was analyzed for a particular collagen. The collagen amount was found to be normally distributed with a mean of 77 and standard deviation of 9.8 grams per mililiter.

(a) What is the probability that the amount of collagen is greater than 68 grams per mililiter?

(b) What is the probability that the amount of collagen is less than 80 grams per mililiter?

(c) What percentage of compounds formed from the extract of this plant fall within 2 standard deviations of the mean?

What Percentage Of Compounds Formed From The Extract Of This Plant Fall Within 2 Standard Deviations Of The Me?

PostPosted: Wed Oct 11, 2017 6:57 am
by Hadley
I assume that the sample is being drawn from a normal distribution. You do not need to know the mean and standard deviation to answer this question. So the question being asked is ?What percentage falls within one standard deviation??. P(-1

What Percentage Of Compounds Formed From The Extract Of This Plant Fall Within 2 Standard Deviations Of The Me?

PostPosted: Wed Oct 11, 2017 7:29 am
by Enyeto
a - 82%

b - 62%

c - 95% by definition

On ti 84 you need the "normalcdf" function which can be accessed by "catalog."

It requires 4 entries: lower bound, upper bound, mean, and standard deviation (separated by commas)

If you're looking for the percent that is greater than a given entry, the upper bound will be infinity.
If you're looking for a percent that is lower than a given entry, the lower bound will be zero.