Posts Tagged ‘Minitab’
Fractional Factorial Designs with Minitab
What Are Fractional Factorial Experiments? In simple terms, a fractional factorial experiment is a subset of a full factorial experiment. [unordered_list style=”star”] Fractional factorials use fewer treatment combinations and runs. Fractional factorials are less able to determine effects because of fewer degrees of freedom available to evaluate higher order interactions. Fractional factorials can be used…
Read MoreFull Factorial DOE 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…
Read MoreLogistic 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…
Read MoreStepwise Regression with 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: [unordered_list style=”star”] F-test T-test R-square AIC [/unordered_list] Three Approaches…
Read MoreMultiple 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: [unordered_list style=”star”] Simple linear regression only has one predictor. Multiple…
Read MoreSimple 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…
Read MoreCorrelation Coefficient with Minitab
Pearson’s Correlation Coefficient Pearson’s correlation coefficient is also called Pearson’s r or coefficient of correlation and Pearson’s product moment correlation coefficient (r), where r is a statistic measuring the linear relationship between two variables. What is Correlation? Correlation is a statistical technique that describes whether and how strongly two or more variables are related. Correlation…
Read MoreTwo Sample Proportion Test with Minitab
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 MoreBox Cox Transformation with Minitab
What is a Box Cox Transformation? [unordered_list style=”star”] Data transforms are usually applied so that the data appear to more closely meet assumptions of a statistical inference model to be applied or to improve the interpret-ability or appearance of graphs. Power transformation is a class of transformation functions that raise the response to some power.…
Read MoreChi Square Test with Minitab
Chi Square (Contingency Tables) We have looked at hypothesis tests to analyze the proportion of one population vs. a specified value, and the proportions of two populations, but what do we do if we want to analyze more than two populations? A chi-square test is a hypothesis test in which the sampling distribution of the…
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