A process that produces mirrors for automobiles is monitored by taking samples of 1500 mirrors and counting the total number of visual flaws on all the sample mirrors. Let be the total number of flaws on the mirrors in the th sample. For the last 70 samples, the quantity has been calculated. Compute the center line and the upper and lower control limits for a chart.

Elements of Statistics – Chapter 6 Notes Key Points Density Curves Normal Distribution Standard Normal Curve Standard Normal Table Density Curve A fitted curve in regard to distribution Is ALWAYS ON or ABOVE the horizontal axis Total area under a density curve is always equal to 1 o Density Histogram To determine the density of a class, take the relative frequency and divide by the width of class. AREA = DENSITY x WIDTH Normal Distribution A variable is “normally distributed” if its distribution has the shape of a symmetric curve. o Characterized by its Mean, , and a Standard Deviation, o The Mean