1. suppose that the weights of 5400 registered female labrador retrievers in the united states are distributed normally with a mean of 62.5 lb and a standard deviation of 2.5lb. approximately how many of the labrador retrievers weigh less than 62.

I believe the normal distribution is symmetrical above and below
the mean.  That tells us that in this kind of distribution, the mean
and the median are the same number ... 50% of the population
is below it, and 50% is above it.

So if the female Labs' weight actually follows a 'normal' distribution
with a mean of 62.5 lbs, then 2,700 of them weigh more than 62.5 lbs
and 2,700 of them weigh less than that. 

The standard deviation doesn't matter.  

By the way ... these are beautiful sweet dogs.