Questions for the process capability (Analyze - Quality & Process - Process capability)

[#1]

Hi Super users

I would like to ask some questions for the process capability (Analyze - Quality & Process -  Process capability) 

I have made an summary report & have 2 questions during the process

1. Why should I set alpha level (Significance level)? What does this value mean here? What does it impact for the result?

Actually I changed the value, but cannot find the result changed

2. I could see colors are in the cpk values. I guess Cpk 1.33 is spec & when the value is less than it, yellow color pops up

& less than 1, red color pops up.

Where can I change this color spec? 

Thanks!!

[#2]

https://www.jmp.com/support/help/en/16.0/?os=mac&source=application&utm_source=helpmenu&utm_medium=a...

Specifies the significance level for confidence limits.

Often you can change colors schemes in the preferences and sometimes there are options in the preferences>platforms, but I don't use this platform, so I'm not familiar.

[#3]

To alter the color scheme, choose File->Preferences.  Select Reports on the left.  On the right, click the Manage Rules button.  Choose Capability Index and click Edit.