A machine produces elastic bands with breaking tension normally distributed with mean 45N and standard deviation 4.36N. On a certain day, a sample of 50 was tested and found to have a mean breaking...

A machine
produces elastic bands
with breaking tension
normally distributed
with mean 45N and
standard deviation
4.36N. On a certain day,
a sample of 50 was
tested and found to
have a mean breaking
tension of 43.46N. Test
at 5% level of
significance whether
this indicates a change
in the mean