Experiment or Observational Study
A meat processing plant has processed an average of 100 tons
per day for the last several years. Newer processing machines have been
installed recently. The quality control manager would like to know whether this
average has improved. She randomly selects 40 days from the computer database
and computes the average and standard deviation of n = 40 days to be 105 tons
and 8 tons, respectively. Is this an experiment or an observational study and
why?





