Percentiles
Is the 15th percentile bad when ranking a country on poverty?
Yes, because 85% of countries are better at dealing with poverty.
What is the formula used to calculate a Z-Score?
(Value - Average) / Standard Deviation
How much data lies below the normal distribution line?
All of it
How much data typically lies within 1 standard deviation from the average?
68%
What is the percent of data that lies below the value if the z-score is 2?
Approximately 98%
Many professional schools require applicants to take a standardized test. Several weeks after the test, Pete receives his score report. He got a 63 out of 100, which placed him in the 83rd percentile. This means...
Pete did approximately better than 83% of other students.
What is the z-score if the value is 4, the average is 3, and the standard deviation is 0.5?
2
How many standard deviations do we typically calculate from the average?
3 above and 3 below
How much data lies below one standard deviation from the average?
16%
Which Z-score is closest to the 72nd percentile?
0.6