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Author Archive | Michael Parker

EWMA EQ2

EWMA Chart with Minitab

What is an EWMA Chart? The EWMA chart (Exponentially-Weighted Moving Average Chart) is a control chart monitoring the exponentially-weighted average of previous and present subgroup means. The more recent data get more weight than older data. It detects the shift of the process mean from the process target over time. The underlying distribution of the [...]
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CumSum JMP_1.0

CumSum Chart with Minitab

What is a CumSum Chart? The CumSum chart (also called cumulative sum control chart or CUSUM chart) is a control chart of monitoring the cumulative sum of the subgroup mean deviations from the process target. It detects the shift of the process mean from the process target over time. The underlying distribution of the CuSum [...]
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NP Chart EQ1

NP Chart with Minitab

What is a NP Chart? The NP chart is a control chart monitoring the count of defectives. It plots the number of defectives in one subgroup as a data point. The subgroup size of the NP-chart is constant. The underlying distribution of this control chart is binomial distribution. NP Chart Equations NP-chart Data Point: Center [...]
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P Chart EQ1

P Chart with Minitab

What is a P Chart? The P chart plots the percentage of defectives in one subgroup as a data point. It considers the situation when the subgroup size of inspected units is not constant. The underlying distribution of the P-chart is binomial distribution. P Chart Equations Data Point:         Center Line:   [...]
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U Chart EQ1

U Chart with Minitab

What is a U Chart? The U chart is a type of control chart used to monitor discrete (count) data where the sample size is greater than one, typically the average number of defects per unit. Defect vs. Defective Remember the difference between defect and defective? A defect of a unit is the unit’s characteristic [...]
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IR chart EQ0

IR Chart with Minitab

What is an IR Chart? The IR chart (also called individual-moving range chart or I-MR chart) is a popular control chart for continuous data with subgroup size equal to one. The I chart plots an individual observation as a data point. The MR chart plots the absolute value of the difference between two consecutive observations [...]
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Stepwise Regression in Minitab

Stepwise Regression in Minitab

What is Stepwise Regression? Stepwise regression is a statistical method to automatically select regression models with the best sets of predictive variables from a large set of potential variables. There are different statistical methods used in stepwise regression to evaluate the potential variables in the model: Three Approaches to Stepwise Regression How to Use Minitab […]

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Full Factorial EQ1

Full Factorial with Minitab

What is a Full Factorial DOE? In a full factorial experiment, all of the possible combinations of factors and levels are created and tested. For example, for two-level design (i.e.each factor has two levels) with k factors, there are 2k possible scenarios or treatments. Two factors, each with two levels, we have 22 = 4 treatments […]

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LGR2

Logistic Regression with Minitab

What is Logistic Regression? Logistic regression is a statistical method to predict the probability of an event occurring by fitting the data to a logistic curve using logistic function. The regression analysis used for predicting the outcome of a categorical dependent variable, based on one or more predictor variables. The logistic function used to model […]

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Multiple Linear Regression EQ1

Multiple Linear Regression with Minitab

What is Multiple Linear Regression? Multiple linear regression is a statistical technique to model the relationship between one dependent variable and two or more independent variables by fitting the data set into a linear equation. The difference between simple linear regression and multiple linear regression: Simple linear regression only has one predictor. Multiple linear regression [...]
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Simple Linear Regression EQ1

Simple Linear Regression with Minitab

What is Simple Linear Regression? Simple linear regression is a statistical technique to fit a straight line through the data points. It models the quantitative relationship between two variables. It is simple because only one predictor variable is involved. It describes how one variable changes according to the change of another variable. Both variables need [...]
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Mann Whitney SXL_00

Mann Whitney Testing with Minitab

What is the Mann Whitney Test? The Mann Whitney test (also called Mann–Whitney U test or Wilcoxon rank-sum test) is a statistical hypothesis test to compare the medians of two populations that are not normally distributed. In a non-normal distribution, the median is the better representation of the center of the distribution. Null Hypothesis (H0): η1 [...]
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