Answer
mean=215.0
standard deviation=20.8
All the data are within 2 standard deviations.
Chebyshev’s theorem:predicts that at least $75\%$ of the data fall within 2 standard deviations.
It seems Chebyshev’s theorem did not work well for this case.
Work Step by Step
mean=215.0
standard deviation=20.8
within 2 standard deviations of the mean: 173.4 to 256.6 contains all the data points,
Chebyshev’s theorem: for $k=2$, $1-1/2^2=0.75$, at least $75\%$ of the data fall within 2 standard deviations.
It seems Chebyshev’s theorem did not work well for this case.
