SOLUTION: The mean of a distribution is 100 and the standard deviation is 10. Which of the following values is unusual? A.130 B.80 C.120 D.90 can you please explain how to do

Algebra ->  Probability-and-statistics -> SOLUTION: The mean of a distribution is 100 and the standard deviation is 10. Which of the following values is unusual? A.130 B.80 C.120 D.90 can you please explain how to do       Log On


   



Question 667100: The mean of a distribution is 100 and the standard deviation is 10. Which of the following values is unusual?
A.130
B.80
C.120
D.90
can you please explain how to do this, i dont understand it.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
Important to Understand z -values as they relate to the Standard Normal curve:
Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.
Note: z = 0 , 50% of the area under the curve is to the left and 50% to the right

For the normal distribution:
one standard deviation from the mean accounts for about 68.2% of the set
two standard deviations from the mean account for about 95.4% of the set****
and three standard deviations from the mean account for about 99.7%.
μ = 100 , σ = 10
A. 130 > 3 standard deviations from the mean...comparatived to the others listed ... UNUSUAL