The difference between the upper and lower control limits of an X-bar chart for a process is 10 units. The quality engineer monitoring the process has been collecting samples of size 7 every hour for the past several months. What is the implied average range from the above results (assume z= 3)?

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.