In a random sample of 12 adults from the United States the m

In a random sample of 12 adults from the United States, the mean waste recycled per person per day was 1.46 pounds and the standard deviation was 0.28 pound. The population is normally distributed. When constructingthe 90% confidence interval estimating the population mean, the critical value is

Solution

When constructingthe 90% confidence interval estimating the population mean, the critical value is

t(0.90,12-1)

=t(0.90,11)

=1.796(for two tailed test)

=1.363(for one tailed test)