Changelog

Below you can find our record of all notable changes made to the Statkat website. Please send us any comments/feedback/bugs via our contact form. Thank you!

##### Statkat Version 5.1.1 - Sep 23, 2020 - updates

- Interactive graphs added for bernoulli distribution and binomial distribution

##### Statkat Version 5.1 - July 21, 2020 - updates

- Online calculators added for p values and critical values

##### Statkat Version 5.0.1 - June 30, 2020 - updates

- Switched up the colors of the simple regression lines in the interactive graphs for regression with two independent variables and regression with moderation effect

##### Statkat Version 5.0.0 - May 26, 2020 - updates

- Wiki section added

##### Statkat Version 4.0.4 - April 22, 2020 - updates

- Interactive visualization added for regression with a categorical IV with 3 groups

##### Statkat Version 4.0.3 - April 19, 2020 - updates

- Interactive visualization added for regression with a categorical IV with 2 groups

##### Statkat Version 4.0.2 - April 9, 2020 - updates

- Interactive visualization added for regression with moderation effect

##### Statkat Version 4.0.1 - April 3, 2020 - updates

- Interactive visualization of the regression equation added for one independent variable and two independent variables

##### Statkat Version 4.0 - Jan 3, 2020 - updates

- Website updated from Bootstrap 3 to Bootstrap 4.4.1

##### Statkat Version 3.0 - Oct 28, 2018 - updates

- Learning tips added

##### Statkat Version 2.23 Beta - Aug 17, 2018 - updates

- Exercise overview tables added

##### Statkat Version 2.22 Beta - July 22, 2018 - updates

- One question added for hierarchical regression analysis. Total number of practice questions in the database = 198.

##### Statkat Version 2.21 Beta - July 17, 2018 - updates

- Explanation how to compute the sum of squares in one way ANOVA added.
- One question added $z$ test for the difference between two proportions. Total number of practice questions in the database = 197.

##### Statkat Version 2.20 Beta - July 10, 2018 - updates

- Two questions added about the binomial test. Two questions added about the paired sample $t$ test. Two questions added about the two sample $t$ test: equal variances not assumed (assumptions). Two questions added about the two sample $t$ test: equal variances assumed (assumptions). Total number of practice questions in the database = 196.

##### Statkat Version 2.19 Beta - June 28, 2018 - updates

- Three questions added about the sign test. Total number of practice questions in the database = 188.

##### Statkat Version 2.18 Beta - June 25, 2018 - updates

##### Statkat Version 2.17 Beta - June 6, 2018 - updates

- Two questions added for OLS regression analysis (assumptions). Total number of practice questions in the database = 183.

##### Statkat Version 2.16 Beta - May 28, 2018 - updates

- Overview table added for one sample Wilcoxon signed-rank test
- Introduction video added to home page

##### Statkat Version 2.15 Beta - May 17, 2018 - updates

- Overview table added for Spearman's rho
- Three questions added for the Pearson correlation coefficient. Total number of practice questions in the database = 181.

##### Statkat Version 2.14 Beta - May 11, 2018 - updates

- Overview tables added for Friedman test, Cochran's Q test, and Marginal Homogeneity test (Stuart-Maxwell test)
- Links added in overview tables for sign test and McNemar's test to find exact $p$ values

##### Statkat Version 2.13 Beta - April 30, 2018 - updates

- Bug fixed: in answer options, lower bound of a confidence interval is now always smaller than the upper bound of the condfidence interval

##### Statkat Version 2.12 Beta - April 27, 2018 - updates

- Overview tables added for Wilcoxon signed-rank test and sign test
- Brief SPSS guides added in most of the overview tables

##### Statkat Version 2.11 Beta - April 19, 2018 - updates

- Overview table added for McNemar's test.
- Three questions added for ANCOVA. Total number of practice questions in the database = 178.

##### Statkat Version 2.10 Beta - April 12, 2018 - updates

- Three questions added for ANCOVA. Total number of practice questions in the database = 175.

##### Statkat Version 2.9 Beta - April 2, 2018 - updates

- Seven questions added for ANCOVA. Total number of practice questions in the database = 172.

##### Statkat Version 2.8 Beta - March 19, 2018 - updates

- One question added for one sample $t$ test. Two questions added for OLS regression analysis (sum of squares). Total number of practice questions in the database = 165.

##### Statkat Version 2.7 Beta - March 8, 2018 - updates

- One question added for one sample $z$ test. One question added for two sample $t$ test assuming equal population standard deviations. Total number of practice questions in the database = 162.

##### Statkat Version 2.6 Beta - March 2, 2018 - updates

- Two questions added about the one sample $z$ test for the mean (subject power, Type and Type II errors). Total number of practice questions in the database = 160.

##### Statkat Version 2.5 Beta - Feb 22, 2018 - updates

- Three questions added about the one sample $z$ test for the mean. Total number of practice questions in the database = 158.

##### Statkat Version 2.4 Beta - Feb 7, 2018 - updates

- Extra practice material added (new category): drag & drop questions
- Three questions added about the one sample $z$ test for the mean. Total number of practice questions in the database = 155.
- Table added to several overview tables, that explains how to find critical $z$ value

##### Statkat Version 2.3 Beta - Feb 2, 2018 - updates

- Two questions added about chi-squared test for the relationship between two categorical variables. Two questions added for the one sample $t$ test. Total number of practice questions in the database = 152.

##### Statkat Version 2.2 Beta - Jan 25, 2018 - updates

- Three questions added about chi-squared test for the relationship between two categorical variables. Total number of practice questions in the database = 148.
- Bug fixed for question 4 Kruskal-Wallis test: answer options are now all unique.

##### Statkat Version 2.1 Beta - Jan 18, 2018 - updates

- One question added about code variables. One question added about the ANOVA $F$ test. Three questions added about the $z$ test for a single proportion. Total number of practice questions in the database = 145.
- Explanation for question 1 about sum of squares in regression improved.

##### Statkat Version 2.0 Beta - Jan 11, 2018 - updates

- New feature added: test selection tool.
- One question added about the $z$ test for the difference between two proportions. Total number of practice questions in the database = 140.

##### Statkat Version 1.12 Beta - Nov 28, 2017 - updates

- One question added about moderator analysis. One question added about partial and semi-partial correlation. Two questions added about classification tables in logistic regression. Total number of practice questions in the database = 139.

##### Statkat Version 1.11 Beta - Nov 17, 2017 - updates

- Three questions added about $R^2$. One question added about moderator analysis. Total number of practice questions in the database = 135.

##### Statkat Version 1.10 Beta - Nov 10, 2017 - updates

- Two questions added about multicollinearity. One question added about outliers and influential points. Total number of practice questions in the database = 131.

##### Statkat Version 1.9 Beta - Nov 04, 2017 - updates

- Two questions added about multicollinearity. Two questions added about $R^2$. Total number of practice questions in the database = 128.

##### Statkat Version 1.8 Beta - Oct 26, 2017 - updates

- Two questions added about contrasts. Two questions added about multiple comparisons. Total number of practice questions in the database = 124.

##### Statkat Version 1.7 Beta - Oct 19, 2017 - updates

- Two questions added about two way ANOVA table. Two questions added about the interpretation of regression coefficients in a simple regression equation. One question added about the interpretation of the Pearson correlation coefficient. Total number of practice questions in the database = 120.
- ANOVA table added to overview two way ANOVA

##### Statkat Version 1.6 Beta - Oct 16, 2017 - updates

- Question added for one way ANOVA about finding $F$ value and critical value $F^*$, three questions added for regression analysis (OLS) about outlier types. Total number of practice questions in the database = 115.
- Better formulation of null and alternative hypothesis of $\chi^2$ test

##### Statkat Version 1.5 Beta - Oct 3, 2017 - updates

- Question added for one way ANOVA about interpretation of the $p$ value, question added for Correlation about the critical $t$ value

##### Statkat Version 1.4 Beta - Sep 28, 2017 - updates

- Question 1 in Tests and confidence intervals for regression coefficients now uses SPSS table
- Three questions added for Tests and confidence intervals for regression coefficients. Total number of practice questions in the database = 109
- Two sample $t$ test and pooled two sample $t$ test are now called two sample $t$ test: equal variances not assumed and two sample $t$ test: equal variances assumed

##### Statkat Version 1.3 Beta - Sep 21, 2017 - updates

- 2 questions added about effect sizes within one way ANOVA, 2 questions added about effect sizes within two way ANOVA, 1 question added about significance testing for the pearson correlation coefficient. Total number of practice questions in the database = 106

##### Statkat Version 1.2 Beta - Sep 15, 2017 - updates

- Question SE of the mean within one way ANOVA added. Total number of practice questions in the database = 101
- Better description of Stein's $R^2$ in overview table for OLS regression
- Formulation of several questions improved

##### Statkat Version 1.1 Beta - Sep 10, 2017 - updates

- 2 questions added. Total number of practice questions in the database = 100
- Links to practice and overview areas fixed on the homepage
- User feedback buttons added in practice area
- Button jQuery functionality seperated from the interface for Android compatibility