Statistics How To

Statistics Definitions > The proportion variance is a measure of dispersion in a proportion. Variance of a sample proportion is given by the formula [1]: Where: p = true proportion of population individuals with the property. n = sample size. Proportion Variance in Factor Analysis The proportion variance is the variance in all variables that … Read more

Probability Distribution > The array distribution refers to the conditional distribution of independent random variables X1 (given X2, … , Xn). As such, it is often used as a synonym for a conditional distribution (for example, Kotz et al. [1], Giri & Banerjee [2], Wadworth & Bryan [3]). The Encyclopedia of Statistical Sciences [4] gives … Read more

Probability Distribution: List of Statistical Distributions   The alpha distribution has been used for tool wear problems and may be used in modeling lifetimes under an accelerated test condition, even though the mean does not exist. Johnson et al. [2] defines the probability density function (PDF) as: Where Φ is the standard normal distribution. There … Read more

Probability Distributions > The term “Eulerian distribution” may refer to: A distribution used in permutation statistics to count descents, or A Type III (p/q, p) distribution. Eulerian Distribution in Permutation Statistics In permutation statistics, the Eulerian distribution is the classical name for the distribution of the descent statistics. A descent in a permutation α1, α2, … Read more

Hypothesis Testing > The Marascuilo procedure is used when you obtain a significant result (i.e., you reject the null hypothesis) for the chi-squared test for c proportions [1]. In other words, you would use the procedure if the chi-squared test indicated the population proportions are not the same across all groups. The Marascuilo procedure is … Read more

Assumption of Normality > Kolmogorov-Smirnov Test Contents: What is the Kolmogorov-Smirnov Test? How to run the test by hand KS Test in SPSS Using other software K-S Test P-Value Table Advantages and Disadvantages Kolmogorov-Smirnov Distribution What is the Kolmogorov-Smirnov Test? The Kolmogorov-Smirnov Goodness of Fit Test (K-S test) compares your data with a known distribution … Read more

SPSS Tutorial (for Beginners): Intro to SPSS About the SPSS Compute Variable Function Sometimes you may have a data set that doesn’t give you the specific statistic you need. For example, you may have two counts for debt from credit cards and “other”, but you are more interested in the total debt. Or, you may … Read more

Statistics Definitions > Shapiro-Wilk Test Contents: What is the Shapiro-Wilk Test? Shapiro-Wilk in SPSS S-W Test in Other Software What is the Shapiro-Wilk Test? The Shapiro-Wilk test is a way to tell if a random sample comes from a normal distribution. The test gives you a W value; small values indicate your sample is not … Read more

SPSS For Beginners > Fisher’s Exact Test in SPSS Fisher’s Exact Test of Independence is used when you have two nominal variables in SPSS and want to find out if proportions for one variable are different among values of the second variable. For experiments with small numbers of participants (under around 1,000), Fisher’s is more … Read more

SPSS For Beginners > If you have an Excel file and want to run an analysis in SPSS, it’s more convenient to directly import the data rather than having to retype the entries. You can import data from Excel to SPSS in a few simple steps. I’m using SPSS 27 in this example, but this … Read more