1. You manage a call center. You measure customer satisfaction by inviting callers to stay on the line after they are helped, at which time you give them an automated 2-question survey. The other day, there was a huge traffic crash on the freeway near your call center. This caused five of your twenty employees to be late, which caused an increase call in response time, which caused a big dip in customer satisfaction on that day. This is an example of  

Total Quality Management

Common cause variation

Standard deviation

Special cause variation

2. A robot in a food factory places salt on each snack cracker. The amount of salt is measured in milligrams.  The average amount of salt per cracker is 10 milligrams, and the standard deviation around this average is 0.2 milligrams. If the amount of salt per cracker is normally distributed with an average of 10 then we would expect ____ of all crackers to be within three standard deviations of the average (i.e. we'd expect them to have between 9.4 and 10.6 milligrams of salt). Hint: see the slide entitled "Probability."  

95.55%

99.74%

3

0.26%