Question: The daily yield for a local chemical plant has averaged 880 tons for the last several years. The quality control manager would like to know whether this average has changed in recent months....

Question:

The daily yield for a local chemical plant has averaged 880 tons for the last several years. The quality control manager would like to know whether this average has changed in recent months. She randomly selects 50 days from the computer database and computes the average and standard deviation of the       ? = 50 yields as?̅ = 871 tons and ? = 21 tons, respectively. Test the appropriate hypothesis using      ? = 0.05.