All you have to do is learn Chebyshev's theorem in terms of k, then
substitute 2 for k.
Here is Chebyshev's theorem in terms of k:
According to Chebyshev's theorem, the proportion of values
from a data set that is further than standard deviations
from the mean is at most .
Then when you plug in 2 for k, you get:
According to Chebyshev's theorem, the proportion of values
from a data set that is further than standard deviations
from the mean is at most .
or writing for ,
According to Chebyshev's theorem, the proportion of values
from a data set that is further than standard deviations
from the mean is at most .
Or if you prefer a decimal answer:
According to Chebyshev's theorem, the proportion of values
from a data set that is further than standard deviations
from the mean is at most .
Or if you prefer a percent answer:
According to Chebyshev's theorem, the proportion of values
from a data set that is further than standard deviations
from the mean is at most %.
