There are frogs and koi in a pond and the number of frogs and the number of koi in the pond are independent. Let the x represent the number of frogs in any given week, and let y represent the number of koi in any given week. X had a mean of 28 with a standard deviation of 2.7, and y has a mean of 15 with standard deviation of 1.6. Which answer choice correctly calculates and interprets the standard deviation of the difference, D=X-Y?

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

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Needmax recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.