when do we use standard deviation or variance to analyze the data? give few examples.
standard deviation and variance measure the spread of the data … meaning they are a way to measure how spread out the data values are.
A set with a smaller standard deviation would indicate the values are less spread out (closer to the mean).
A set with a larger standard deviation would indicate the values are more spread out (farther form the mean).
A practical example could be that
one set of lifetimes of light bulbs has a standard deviation of 520 hours.
And a second set has a standard deviation of 215 hours.
The second set has a smaller standard deviation, so the lifetimes of those lightbulbs are less spread out (and crowded closer to the mean), therefore this second set of lightbulbs has a more “predictable” lifetime.
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thanks for the answer!!