Question 1102156
47.4 is the mean weight. 

The variance is the standard deviation squared, so {{{6.25^2}}} is the standard deviation.

Now, 95% of newborn dolphins should weigh within 2 standard deviations of the mean.

So {{{47.4 - 2(6.25^2)}}} is they smallest the dolphin should weight

and {{{47.4 - 2(6.25^2)}}} is the maximum value the dolphin should weight.

see more about the 68-95-99.7 rule here: So http://www.oswego.edu/~srp/stats/6895997.htm