spc chart CL

[Former Member]

Hi

How can I change how many data points the centre line is calculated over on my SPC chart?

[Former Member]

Dear Nick,

Have you used subgroup size (the number of raw data point to be included in each chart point) under iSPC chart parameter?

it works for me you can get more details in help.

Regards,

Manoj Bilthare

[Former Member]

Thanks Manoj, but I don't think that's what I want.

Say I had 10 data points 11,12,10,8,9,11,10,12,14,13

then the centre line (mean) is obviously 11, but in my scenario I want to display all 10 points on my xbar chart, but I want to calculate my mean (and therefor all my control limits) on only the most recent 5 values, giving a CL of 12.

Nick

[jcgood25]

If this is something on the front-end UI then you will need to disable the auto calc and set them yourself in javascript:

A reverse loop for the last 'n' datapoints should be easy enough.

getUpperNumberOfDataPoints()

getUpperDataValueAt(POINTNUMBER)