Marlon's weight is 39.3 pounds with a mean weight of 40 pounds and a standard deviation of 1.3 pounds.
We know that the formula for calculating a z-score is z = (x-Ī¼)/Ļ, where x is the raw score, Ī¼ is the population mean, and Ļ is the population standard deviation.
Given that mean weight = 40 pounds.
and standard deviation = 1.3 pounds.
Also given that Marlon is heavier than 30% of boys his age on average, according to measurements.
The z value of 30% is -0.524.
We can put this value in the formula.
-0.524 = (x - 40)/1.3
i.e. (-0.524) * 1.3 = x - 40
i.e. - 0.6812 = x - 40
i.e. x = Ā 40 - 0.6812 = 39.3188
Therefore, we can conclude that Marlon's weight is 39.3 pounds with a mean weight of 40 pounds and a standard deviation of 1.3 pounds. So, the last option is correct.
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