Posts by Michael Parker
NP Chart with SigmaXL
What is an 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…
Read MoreXbar S Chart with SigmaXL
What is a Xbar S Chart? The X-S chart (also called Xbar S chart) is a control chart for continuous data with a constant subgroup size greater than ten. The Xbar chart plots the average of a subgroup as a data point. The S chart plots the standard deviation within a subgroup as a data…
Read MoreTwo Sample Proportion with SigmaXL
What is the Two Sample Proportion Test? The two sample proportion test is a hypothesis test to compare the proportions of one certain event occurring in two populations following the binomial distribution. [unordered_list style=”star”] Null Hypothesis(H0): p1 = p2 Alternative Hypothesis(Ha): p1 ≠ p2 [/unordered_list] Two Sample Proportion Test Assumptions [unordered_list style=”star”] The sample data…
Read MoreOne Sample Proportion with SigmaXL
What is the One Sample Proportion Test? One sample proportion test is a hypothesis test to compare the proportion of one certain outcome (e.g. the number of successes per the number of trials, or the number of defects per the total number of opportunities) occurring in a population following the binomial distribution with a specified…
Read MoreOne Sample Wilcoxon with SigmaXL
What is the One Sample Wilcoxon Test? The one sample Wilcoxon test is a hypothesis test to compare the median of one population with a specified value. [unordered_list style=”star”] Null Hypothesis (H0): η = η0 Alternative Hypothesis (Ha): η ≠ η0 [/unordered_list] It is an alternative test of one sample t-test when the distribution of the data is…
Read MoreP Chart with SigmaXL
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: …
Read MoreU Chart with SigmaXL
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…
Read MoreXbar R Chart with SigmaXL
What is a Xbar R Chart? The Xbar R chart is a control chart for continuous data with a constant subgroup size between two and ten. [unordered_list style=”star”] The Xbar chart plots the average of a subgroup as a data point. The R chart plots the difference between the highest and lowest values within a…
Read MoreIR Chart with SigmaXL
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. [unordered_list style=”star”] The I chart plots an individual observation as a data point. The MR chart plots the absolute value of the difference between two…
Read MoreLogistic Regression with SigmaXL
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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