If it

is claimed that the contents
of soaps
boxes sold
weigh on average at least 20 ounces.

The distribution
of weight is known to be normal;

We
assume \sigma = 0.5σ=0.5 is known

n=30
sample
mean
weight =
18.5 ounces.

Test
at
the 10% significance level (\alpha = .10)(α=.10) the null
hypothesis that the population mean weight is at least 20
ounces.