Question 1159553
Because the sd is known, this is a z-interval
The interval is the mean+/-z(0.95)*sigma/sqrt(n)
the half-interval or the margin of error is 1.645*12/sqrt(60)
=2.548 or 2.55
(57.45, 62.55) or (57.5, 62.4), the asymmetry being due to rounding.