mqr.spc.rules.

n_1side

mqr.spc.rules.n_1side(n)

Rule monitoring the count on one side the centreline.

This function returns an alarm rule that alarms when n statistics in a row fall on one side of the centreline.

This function generates a rule. The result of this function is another function that can be passed to mqr.plot.spc.alarms or combine.

Parameters:

nint

Number of consecutive statistics falling on one side of the centreline required to trigger an alarm.

Returns:

Callable[(ControlStatistic, ControlParams), pandas.Series[bool]]

A function taking a control statistic and the params used to create them, and returning a series with True marking alarms.

Examples

data = pd.DataFrame({
    'Xbar': np.array([9, 10, 11, 13, 12, 8])
#                            ^^^^^^^^^^ (3 > target)
})

params = mqr.spc.XBarParams(centre=10, sigma=1)
stat = params.statistic(data)
rule = mqr.spc.rules.n_1side(3)

fig, ax = plt.subplots(figsize=(7, 3))
mqr.plot.spc.chart(stat, params, ax=ax)
mqr.plot.spc.alarms(stat, params, rule, ax=ax)

(Source code, png, pdf)