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Remove p and np conformant limits [#25]
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sql/02-spc-intermediates-schema.sql

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Original file line numberDiff line numberDiff line change
@@ -208,7 +208,6 @@ create view spc_intermediates.fraction_conforming_sample_statistics as
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-- every sample has been reduced to a single number, being the fraction.
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create view spc_intermediates.conformant_limit_establishment_statistics as
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select w.id as limit_establishment_window_id
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, avg(mean_fraction_conforming) as grand_mean_conforming
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, avg(mean_fraction_non_conforming) as grand_mean_non_conforming
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, avg(sample_size) as mean_sample_size
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from spc_intermediates.fraction_conforming_sample_statistics fcss
@@ -217,21 +216,6 @@ create view spc_intermediates.conformant_limit_establishment_statistics as
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and fcss.include_in_limit_calculations
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group by w.id;
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-- For each limit establishment window, this view derives the p chart upper control limit, center line and lower control
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-- limit for fraction conforming (aka a yield chart). The limits are based on a function of the grand mean of fractions
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-- conforming.
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--
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-- This chart is not very commonly used; it is more traditional to use the fraction non-conforming for control. This is
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-- included mostly for completeness.
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create view spc_intermediates.p_limits_conformant as
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select limit_establishment_window_id
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, grand_mean_conforming + (3 * (sqrt((grand_mean_conforming * (1.0 - grand_mean_conforming)) /
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mean_sample_size))) as upper_limit
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, grand_mean_conforming as center_line
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, greatest(0.0, grand_mean_conforming - (3 * (sqrt((grand_mean_conforming * (1.0 - grand_mean_conforming)) /
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mean_sample_size)))) as lower_limit
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from spc_intermediates.conformant_limit_establishment_statistics;
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-- For each limit establishment window, this view derives the p chart upper control limit, center line and lower control
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-- limit for fraction non-conforming (aka a fallout chart). The limits are based on a function of the grand mean of
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-- fractions non-conforming.
@@ -249,20 +233,6 @@ create view spc_intermediates.p_limits_non_conformant as
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-- np charts
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-- For each limit establishment window, this view derives the np chart (number conforming) upper control limit, center
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-- line and lower control limit. Note that the p chart and np chart can disagree on whether a sample is in-control or
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-- not, because the limits are calculated as decimals but samples are composed of an integer number of inspected items.
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--
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-- This is the conforming version of an np chart, rarely used.
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create view spc_intermediates.np_limits_conformant as
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select limit_establishment_window_id
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, (grand_mean_conforming * mean_sample_size) +
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(3 * (sqrt((grand_mean_conforming * mean_sample_size) * (1.0 - grand_mean_conforming)))) as upper_limit
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, grand_mean_conforming * mean_sample_size as center_line
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, greatest(0.0, (3 * (sqrt((grand_mean_conforming * mean_sample_size) *
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(1.0 - grand_mean_conforming))))) as lower_limit
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from spc_intermediates.conformant_limit_establishment_statistics;
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-- For each limit establishment window, this view derives the np chart (number non-conforming) upper control limit,
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-- center line and lower control limit. Note that the p chart and np chart can disagree whether a sample is in-control
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-- or not, because the limits are calculated as decimals but samples are composed of an integer number of inspected

sql/03-spc-reports-schema.sql

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Original file line numberDiff line numberDiff line change
@@ -127,34 +127,6 @@ create view spc_reports.s_rules as
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join spc_intermediates.s_limits on limits_w.id = s_limits.limit_establishment_window_id
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where include_in_limit_calculations;
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-- This view applies the limits derived in p_limits_conformant to matching control windows, showing which sample
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-- fractions conforming were in-control and out-of-control according to the limits on the fraction conforming.
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--
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-- This is a non-traditional application, the typical approach is to set rules on fraction non-conforming. This is
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-- included for completeness.
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create view spc_reports.p_conformant_rules as
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select ss.sample_id
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, control_w.id as control_window_id
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, limits_w.id as limit_establishment_window_id
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, i.id as instrument_id
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, center_line
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, mean_fraction_conforming as controlled_value
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, lower_limit
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, upper_limit
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, case
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when mean_fraction_conforming > upper_limit then 'out_of_control_upper'
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when mean_fraction_conforming < lower_limit then 'out_of_control_lower'
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else 'in_control'
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end as control_status
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from spc_intermediates.fraction_conforming_sample_statistics ss
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join spc_data.windows control_w on ss.window_id = control_w.id
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join spc_data.window_relationships wr on control_w.id = wr.control_window_id
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join spc_data.windows limits_w
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on limits_w.id = wr.limit_establishment_window_id
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join spc_data.instruments i on control_w.instrument_id = i.id
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join spc_intermediates.p_limits_conformant on limits_w.id = p_limits_conformant.limit_establishment_window_id
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where include_in_limit_calculations;
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-- This view applies the limits derived in p_limits_non_conformant to matching control windows, showing which sample
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-- fractions non-conforming were in-control and out-of-control according to the limits on the fraction non-conforming.
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create view spc_reports.p_non_conformant_rules as
@@ -181,34 +153,6 @@ create view spc_reports.p_non_conformant_rules as
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on limits_w.id = p_limits_non_conformant.limit_establishment_window_id
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where include_in_limit_calculations;
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-- This view applies the limits derived in np_limits_conformant to matching control windows, showing which sample counts
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-- conforming were in-control and out-of-control according to the limits on the count conforming.
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--
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-- This is a non-traditional application, the typical approach is to set rules on fraction non-conforming. This is
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-- included for completeness.
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create view spc_reports.np_conformant_rules as
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select ss.sample_id
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, control_w.id as control_window_id
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, limits_w.id as limit_establishment_window_id
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, i.id as instrument_id
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, center_line
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, mean_fraction_conforming * sample_size as controlled_value
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, lower_limit
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, upper_limit
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, case
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when (mean_fraction_conforming * sample_size) > upper_limit then 'out_of_control_upper'
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when (mean_fraction_conforming * sample_size) < lower_limit then 'out_of_control_lower'
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else 'in_control'
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end as control_status
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from spc_intermediates.fraction_conforming_sample_statistics ss
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join spc_data.windows control_w on ss.window_id = control_w.id
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join spc_data.window_relationships wr on control_w.id = wr.control_window_id
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join spc_data.windows limits_w
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on limits_w.id = wr.limit_establishment_window_id
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join spc_data.instruments i on control_w.instrument_id = i.id
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join spc_intermediates.np_limits_conformant on limits_w.id = np_limits_conformant.limit_establishment_window_id
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where include_in_limit_calculations;
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-- This view applies the limits derived in np_limits_non_conformant to matching control windows, showing which sample
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-- counts non-conforming were in-control and out-of-control according to the limits on the counts non-conforming.
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create view spc_reports.np_non_conformant_rules as

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