Which of the following is true about one-tailed and two-tailed tests?
A) For standard normal and t-distributions, which have a mean of zero, lower-tail
critical values are negative and upper-tail critical values are positive.
B) For an upper one-tailed test, if the test statistic is greater than the critical value, the
decision would be to fail to reject the null hypothesis.
C) For a lower one-tailed test, if the test statistic is less than the critical value, the
decision would be to fail to reject the null hypothesis.
D) For a two-tailed test, if the test statistic is either greater than the upper critical value
or less than the lower critical value, the decision would be to fail to reject the null
hypothesis.
Which of the following is true of calculating confidence intervals for larger samples?
A) For larger samples, the t-distribution is indistinguishable from the standard normal
distribution.
B) For larger samples, both the t-distribution and the standard normal distribution
require standard deviation values to be calculated.
C) For larger samples, the degrees of freedom cannot be calculated accurately.
D) For larger samples, only z-values provide a true sampling distribution of the mean.
Pickson Luthiers Corporation makes four models of electric guitars, ScarCT, Dela Mort,
Warax, and Invazen. Each guitar must flow through five departments, assembly,
painting, sound testing, inspection, and packaging. The table below shows the relevant