Question

A manufacturer of cell phone screens is concerned because 12 percent of the screens manufactured using a previous process were rejected at the final inspection and could not be sold. A new process is introduced that is intended to reduce the proportion of rejected screens. After the process has been in place for several months a random sample of 100 screens is selected and inspection. Of the 100 screens 6 are rejected. What are the appropriate hypotheses to investigate whether the new process reduces the population proportion of screens that will be rejected

Answer 1

Null hypothesis: There is no significant association between the existing process and the new process for reducing the population proportion of screens that will be rejected .

Alternative hypothesis :There is a significant association between the existing process and the new process for reducing the population proportion of screens that will be rejected .

Finally the null hypothesis will be rejected and we should accept the alternate hypothesis

Step-by-step explanation:  

In the existing process the sample size and population was not known.,but the percentage of rejected screens were given as 12%.,but in the new process out of 100 screens only 6 are rejected

 percentage of rejected screens using new process = 6÷ 100 ×100 = 6%  

 percentage of rejected screens using existing (old) process = 12%

so the new process is the effective one which reduces the rejection rate of screens., hence it is concluded that There is a significant association between the existing process and the new process for reducing the population proportion of screens that will be rejected .

so the null hypothesis will be rejected and we should accept the alternate hypothesis