Assignment Task: The production manager at Oliver Steel, a manufacturer of wheelchairs, wants to compare the number of defective wheelchairs produced on the day shift with the number on the night shift. A sample of the production from six day shifts and eight night shifts revealed the following number of defects.
Day 5 8 7 6 9 7
Night 8 10 7 11 9 12 14 9
At the 0.5% significance level, the production manager wants to know whether the day shift is less than the night shift in the mean number of defects.
a) State the null hypothesis and the alternate hypothesis.
b) What is the decision rule?
c) What is the value of the test statistic?
d) What is your decision regarding the null hypothesis?
e) Interpret the result.
f) What assumptions are necessary for this test?