Answer
a) .4129
b) 25
c) 19
d) They need to be updated.
Work Step by Step
a) We first find the z-score:
$z=\frac{174-182.9}{40.8}=-.22$
Using the table of z-scores, we see that this corresponds to .4129.
b) The number is:
$=\frac{3500}{140}=25$
c) The new number with the new mean is:
$=\frac{3500}{182.9}=19$
d) It is necessary to review safety regulations since the ability of the boats as well as the mean weight of people changes over time.
