# Statistical Methods

We are expert in selecting proper statistical analysis for a given research question and data set. Our goal is to perform virtually any conventional statistical analysis for our Clients. We produce a very clear report on the basis of the data. We demonstrate how to interpret each type of statistical procedure, we create necessary graphs.

### Our services include:

1. Research design

We give advice about a proposed design and statistical analysis: We define population of study, choose a method of sampling, edit hypotheses, run power analyses, suggest statistical method. We help in preparing SAP (statitsical analysis plan)

2. Test/Survey/CRF/eCRF Construction
3. Construction of a Data File

We create a data file that will be used for data entry and give instructions for data entry according to the survey or CRF. Proper data entry is the key point of each analysis.

4. Data Analysis

We analyse the data, apply statistical methods and write statistical report. It includes tables edition and graphs creating.

5. Professional editing

We are familiar with the APA format for scientific writing.

Common statistical methods which we use:

• Descriptive statistics (mean, median, mode, SD, SE, 95%CI for mean)
• t-test (paired sample or independent sample t-test)
• Chi-square test (crosstab analysis, Cramer's V)
• ANOVA (analysis of variance), MANOVA (including: Bonferroni test ,LSD test, Tukey's test)
• Factor Analysis
• Cluster Analysis k-means cluster, hierarchical cluster
• Discriminant analysis
• Reliability Analysis
• Linear Regression (multiple regression)
• Curve estimation
• Chi-square test (crosstab analysis, Cramer's V)
• ANOVA, MANOVA (post hoc: Bonferroni test, LSD test, Tukey's test)
• Factor Analysis
• Cluster Analysis k-means cluster, hierarchical cluster
• Discriminant analysis
• Logistic Regression: logit, probit, tobit model, Odds Ratio
• Correlation: Spearman, tau-b-Kendall, Pearson.

Nonparameric tests:

• Kolmogorov - Smirnov Z (normality analysis)
• Mann-Whitney test (the U test)
• Kruskal-Wallis test, Wilcoxon Signed-Ranks test
• McNemar's Test
• Friedman's Test
• Median test
• Regression trees
• Multidimensional Scaling
• Survival Analysis
• Quality Control Charts
• Power analysis
• Equivalence and bioequivalence analysis (Schuirmann's test)
• Survival analysis, Cox regression, Kaplan -Meier survival
• Econometric models
• Time Series Analysis (forecasting, ARIMA, Spectrum/Fourier analysis)
• Data Mining.