In the manufacturing process of carbon composition resistorshistorical records indicate that 80% of these components havesuperior quality, 10% have very good quality, 5% have marginalquality and 5% are poor (non-shippable). A quality control firmimplemented changes to the manufacturing plant (like installingdehumidifiers) and several months later a random sample of 1200carbon composition resistors we gathered and rated. Here’s what wasfound:
Superior:996 Very good:126 Marginal:48 Poor:30 Total:1200
Answer the following questions below.
(a) Test if there is evidence to suggest that the implementedchange changed the distribution. Use ? = .05.
(b) Looking at each of the (Xi?Ei)2 , which is the largest andconstruct a 95% confidence interval the multi- Ei
nomial proportion corresponding this ratio.
(c) Would you believe that the installation of dehumidifiersimproved the quality? Briefly explain.
