Re: A certain list of 200 test scores has an average

Standard deviation is a measurement of how far the values are from the mean

So the smaller the standard deviation it indicates that the values are closer to the value of the mean and the larger the standard deviation, it tells us that the values are farther away from the mean

Keeping this principle in mind, the above set has a mean of 85 and sd = d.

In order to decrease the standard deviation, the two values that we pick must be very close to the mean hence Choice D is the best answer