STATISTICAL TECHNIQUES AND TOOLS
MEASURES OF CENTER AND SPREAD
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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mean will increase, standard deviation will increase
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mean will increase, standard deviation will decrease
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mean will increase, standard deviation will stay the same
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mean will decrease, standard will decrease
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Detailed explanation-1: -One student was absent on the test day, and his score wasn’t included in the calculation. If his score of 84 was added to the distribution of scores, what would happen to the mean and standard deviation? (a) Mean will increase, and standard deviation will increase.
Detailed explanation-2: -This rule tells us that around 68% of the data will fall within one standard deviation of the mean; around 95% will fall within two standard deviations of the mean; and 99.7% will fall within three standard deviations of the mean.
Detailed explanation-3: -One standard deviation below the mean is the mean minus one standard deviation. Imagine you have calculated the mean to 576 and the standard deviation to be 121. One standard deviation below the mean is 576-121 = 455.