Hajo Schmidt

Einstein once  said about assumption of nature laws:

– In most cases the nature says: „You are wrong „ (we assume the alternative hypothesis)

– In some cases the nature says: „Maybe you are right“ (we assume the null hypothesis)

– But the nature never says: „Yes, you are right“ (two things are equal)

By principle you can only state that s…[Read more]

@rbutler, thanks for your statement. Myself I work in the german automotive industry where one’s requires at least 125 data points for the capability analysis. In many cases we have much higher sample sizes.
I made a simulation with normally distributed random data, sample size 30. See pic enclosed. I wonder that you can accept such a high 95%CI.…[Read more]

@rbutler In fact you won’t find “>2000 data point” in the literature. It is my own advice because otherwise the number of data at the boarders becomes very low (0,00135 * 2000 = 2,7) and the percentile-value will be very sensitive to rare events.
In fact if you have fewer data points you have to extrapolate either by finding a suitable fit or by…[Read more]

Hi KKiru,

if you have a sufficient amount of data (appr. > 2000) you can calculate the capability directly from the data without any distribution or transformation using the “Quantile”-methode and calculating the 0,135%- and 99,865%-percentile values in Minitab.
In case of fever data you have to find an appropriate fit of the data (especially at…[Read more]