If the mean is 20.8, one standard deviation each way is adding and subtracting 3.1, so 17.7 and 23.9 (68% of values)
Two standard deviations adding and subtracting 3.1*2 = 6.2, or 14.6 and 27.
Three standard deviations is 11.5 and 30.1
So we have
11.5 - 14.6 - 17.7 - 20.8 - 23.9 - 27 - 30.1
Going left to 11.5 is 3 standard deviations out, so 99.7/2 = 49.85%
Going right to 27 is 2 standard deviations out, so 95/2 = 47.5%
Add those two % to get 97.32%
This is hard to do without a picture so I hope that helps!
Get it sis 57
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Answer:
A. 
Step-by-step explanation:
We want to find the Z-score of 
if the population mean is 
,and the population standard deviation is 
.
We use the formula:
We substitute the values to obtain:
The correct answer is A.
Answer:
-2(2x-1)
Step-by-step explanation:
x+4-5x-2
1) collect like like terms
-4x+2
2) factor out the -2
-2(2x-1)
3) that gives you the final answer of
-2(2x-1)
