Posts Tagged ‘How To’
Mann Whitney Testing with SigmaXL
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. [unordered_list style=”star”] Null…
Read MoreOne Way ANOVA with SigmaXL
What is One Way ANOVA? One way Analysis of Variance is a statistical method to compare means of two or more populations. It is a generalized form of the two sample t-test since a two sample t-test compares two population means and one way ANOVA compares k population means where k ≥ 2. [unordered_list style=”star”] Null Hypothesis…
Read MorePaired t Test with SigmaXL
Paired t Test The third type of a Two Sample t-Test is the Paired t Test. This test is used when the two populations are dependent of each other, so each data point from one distribution corresponds to a data point in the other distribution. When using a paired t test, the test statistic is calculated…
Read MoreTwo Sample t Test with SigmaXL
Two Sample t Test Two sample t test is a hypothesis test to study whether there is a statistically significant difference between the means of two populations. [unordered_list style=”star”] Null Hypothesis (H0): μ1 = μ2 Alternative Hypothesis (Ha): μ1 ≠ μ2 [/unordered_list] Where: μ1 is the mean of one population and μ2 is the mean…
Read MoreOne Sample t Test with SigmaXL
What is a One Sample t Test? A One sample t test is a hypothesis test to study whether there is a statistically significant difference between a population mean and a specified value. [unordered_list style=”star”] Null Hypothesis (H0): μ = μ0 Alternative Hypothesis (Ha): μ ≠ μ0 [/unordered_list] Where: [unordered_list style=”star”] μ is the mean…
Read MoreCentral Limit Theorem with SigmaXL
Central Limit Theorem The Central Limit Theorem is one of the fundamental theorems of probability theory. It states a condition under which the mean of a large number of independent and identically-distributed random variables, each of which has a finite mean and variance, would be approximately normally distributed. Let us assume Y1, Y2 . .…
Read MoreMulti Vari Analysis with SigmaXL
Multi-Vari Analysis Multi Vari Analysis is a graphic-driven method to analyze the effects of categorical inputs on a continuous output. It studies how the variation in the output changes across different inputs and helps us quantitatively determine the major source of variability in the output. Multi Vari charts are used to visualize the source of…
Read MoreCapability Analysis with SigmaXL
Process Capability Process capability measures how well the process performs to meet given specified outcome. It indicates the conformance of a process to meet given requirements or specifications. Capability analysis helps to better understand the performance of the process with respect to meeting customer’s specifications and identify the process improvement opportunities. Process Capability Analysis Steps…
Read MoreVariable Gage R&R with SigmaXL
Variable Gage R&R Variable Gage Repeatability & Reproducibility (Gage R&R) is a method used to analyze the variability of a measurement system by partitioning the variation of the measurements using ANOVA (Analysis of Variance). Whenever something is measured repeatedly or by different people or processes, the results of the measurements will vary. Variation comes from…
Read MoreRun Chart with SigmaXL
Why we use a Run Chart A run chart is a chart used to present data in time order. These charts capture process performance over time. The X axis indicates time and the Y axis shows the observed values. A run chart is similar to a scatter plot in that it shows the relationship between X and…
Read More