7. Ten samples of 15 parts each were taken from an ongoing process to establish a p-chart for control. a. Develop a p-Chart for 95 percent confidence (1.96 standard deviation). b. Based on the plotted data points, what comments can you make

Hello the table related to your question is attached below

a) attached below

b) The process is out of control because two ( 2 ) values from the defect rate table are out of the control limits at 95% as seen in the p-chart in question ( A )

Step-by-step explanation:

a) p-chart for 95% confidence

std = 1.96

Total defects = ∑ number of defective items in the sample = 10

number of samples = 10

sample size ( n ) = 15

The P value for the process is calculated as :

Total defects / ( number of sample * sample size )

= 10 / ( 15 * 10 ) = 10 / 150 = 0.067

standard deviation ( σ ) =  =  0.065

next we determine the limits ( i.e. upper and lower )

UCL = p + zSp = 0.067 + 1.96(0.065 ) = 0.194

LCL = p - zSp = 0.067 - 1.96(0.065) = -0.060 ≈ 0 ( because LCL ≠ negative)

attached below is the required p-chart

b) The process is out of control because two ( 2 ) values from the defect rate table are out of the control limits at 95% as seen in the p-chart in question ( A )