Short Notes about Statistical Analysis TEST

 

 Statistical Analysis

Test/Method : Descriptive statistics

Purpose : Summarizes and describes the main features of a dataset.

Type : Measures of central tendency (mean, median, mode), Measures of variability (range, variance, standard deviation), Distribution (skewness, kurtosis),  Frequency Distribution (Frequency tables, Histograms, Bar Charts.)

Assumption: No specific assumptions since descriptive statistics do not infer beyond the data. - Assumes data is appropriate for the specific measures (e.g., interval/ratio scale for mean, variance).

Application : Provides a summary of data characteristics before conducting inferential statistical analyses.  - Used in initial data exploration to understand the basic structure and distribution of data. - Helps in identifying outliers, trends, and patterns in the data.  - Commonly applied in reports, presentations, and research

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Test/Method : Chi-square test

Purpose : Tests the association between categorical variables.

Type : Pearson's Chi-square, Chi-square for independence, Chi-square for goodness-of-fit

Assumption: Expected frequencies should be ≥ 5 in each cell, independence of observations

Application : Used in contingency tables, goodness-of-fit tests for categorical data.

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Test/Method : Student t-test

Purpose : Compares the means of two groups to see if they are significantly different.

Type : Independent samples t-test, Paired samples t-test, One-sample t-test

Assumption: Normality, equal variances (for independent t-test), independence of observations.

Application : Comparing means between two groups (e.g., control vs. treatment).

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Test/Method : ANOVA (Analysis of Variance) 

Purpose : Compares means among three or more groups.

Type : One-way ANOVA, Two-way ANOVA, Repeated Measures ANOVA

Assumption: Normality, homogeneity of variance, independence of observations.

Application : Comparing means across multiple groups or factors.

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Test/Method : Correlation

Purpose : Measures the strength and direction of a linear relationship between two continuous variables.

Type : Pearson's, Spearman's, Kendall's

Assumption: Linear relationship, normality (for Pearson's), no significant outliers

Application : Assessing the relationship between variables (e.g., height and weight).

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Test/Method : Regression

Purpose : Models the relationship between a dependent variable and one or more independent variables.

Type : Linear Regression, Multiple Regression, Logistic Regression

Assumption: Linearity, independence, homoscedasticity, normality of residuals (for linear regression).

Application : Predicting an outcome, assessing the impact of predictors.

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Test/Method : Multivariate test (MANOVA, MANCOVA)

 Purpose : Tests for differences in multiple dependent variables across groups (MANOVA), or controlling for covariates (MANCOVA).

Type : MANOVA, MANCOVA

Assumption: Multivariate normality, homogeneity of variance-covariance matrices, independence of observations.

Application : Examining group differences on multiple outcomes, adjusting for covariates.

 

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Test/Method : Validity Test (Factor analysis)

Purpose : Reduces data to a smaller set of underlying factors, tests construct validity.

Type : Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA)

Assumption: Adequate sample size, linearity, Multicollinearity, normality.

Application : Identifying underlying constructs, assessing the validity of measurement instruments.

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Test/Method : Reliability Test (Cronbach’s alpha)

 Purpose : Assesses the internal consistency of a set of items or scale.

Type : Cronbach's Alpha

Assumption: Items should measure the same underlying construct, appropriate for continuous/ordinal data.

Application : Evaluating the reliability of a survey or test.

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Test/Method : Friedman Rank test

Purpose : Non-parametric alternative to the repeated measures ANOVA; compares ranks across multiple groups.

Type : Friedman Test

Assumption: Requires the data to be ordinal or interval, blocks of data should be comparable.

Application : Used when the assumptions of repeated measures ANOVA are not met, analyzing ranked data.

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Test/Method : Structure Equation Modelling (SEM)

Purpose : Analysis complex relationships between observed and latent variables; includes measurement and structural models.

Type : SEM, Path Analysis, Confirmatory Factor Analysis (CFA)

Assumption: Large sample size, normality, no multicollinearity, appropriate model specification.

Application : Modelling complex relationships between variables, used in social sciences, psychology, etc.



Dr. K. Sakkaravarthi
I am Dr. K. Sakkaravarthi, MBA.,MLISc., Ph.D., (Both NET and SET qualified)

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