{"id":3309,"date":"2021-09-22T15:22:00","date_gmt":"2021-09-22T14:22:00","guid":{"rendered":"https:\/\/www.gironi.it\/blog\/?p=3309"},"modified":"2024-11-13T15:25:05","modified_gmt":"2024-11-13T14:25:05","slug":"statistical-parametric-and-non-parametric-tests","status":"publish","type":"post","link":"https:\/\/www.gironi.it\/blog\/en\/statistical-parametric-and-non-parametric-tests\/","title":{"rendered":"Statistical Parametric and Non-Parametric Tests"},"content":{"rendered":" <p><a href=\"https:\/\/www.gironi.it\/blog\/il-test-delle-ipotesi\/\" target=\"_blank\" data-type=\"post\" data-id=\"1190\" rel=\"noreferrer noopener\">Statistical tests<\/a> can be either parametric or non-parametric.<\/p>   <h2 class=\"wp-block-heading\">Parametric Tests: The Power of Normality<\/h2>   <ul class=\"wp-block-list\"> <li><strong>Parametric tests<\/strong> assume an approximately normal distribution.<\/li>   <li>They involve <strong>continuous or interval-type variables<\/strong> and require a sufficiently large sample size (typically > 30).<\/li>   <li>They also assume <strong>homogeneity of variances<\/strong> (<em>homoscedasticity<\/em>).<\/li> <\/ul>   <p>These tests have a <strong>higher statistical power<\/strong> because they provide a greater probability of correctly rejecting a false statistical hypothesis.<\/p>   <!--more-->   <p>Examples of parametric tests we have covered include the <a href=\"https:\/\/www.gironi.it\/blog\/la-distribuzione-normale#zscore\" data-type=\"post\" target=\"_blank\" rel=\"noreferrer noopener\">Z-test for the standardized normal distribution<\/a>, <a href=\"https:\/\/www.gironi.it\/blog\/la-distribuzione-t-e-il-test-delle-ipotesi\/\" data-type=\"post\" data-id=\"1131\" target=\"_blank\" rel=\"noreferrer noopener\">Student&#8217;s t-test<\/a>, <a href=\"https:\/\/www.gironi.it\/blog\/lanalisi-della-varianza-anova-spiegata-semplice\/\" data-type=\"post\" data-id=\"2342\">ANOVA<\/a> (Analysis of Variance), and the <a href=\"https:\/\/www.gironi.it\/blog\/regressione-lineare-semplice\/#il-coefficiente-di-correlazione-r-di-pearson\" data-type=\"post\" target=\"_blank\" rel=\"noreferrer noopener\">Pearson correlation coefficient r<\/a>.<\/p>   <h2 class=\"wp-block-heading\">Non-Parametric Tests: Versatility and Flexibility<\/h2>   <p><strong>Non-parametric tests<\/strong>, on the other hand, do not assume any specific type of distribution and do not require the estimation of statistical parameters such as mean, variance, or standard deviation.<br><br>In simple terms, non-parametric tests can be broadly categorized as follows:<br><br>1) <strong>Goodness-of-fit tests<\/strong> (comparing observed values with expected values).<br>2) Tests that serve as <strong>non-parametric alternatives to parametric tests<\/strong>.<br><\/p>   <p>Examples of non-parametric tests we have discussed, with links for more detailed information, include the <a href=\"https:\/\/www.gironi.it\/blog\/il-test-del-chi-quadrato-bonta-di-adattamento-e-test-di-indipendenza\/\" data-type=\"post\" data-id=\"1516\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Chi-square test<\/strong><\/a>, the <a href=\"https:\/\/www.gironi.it\/blog\/test-non-parametrici-il-test-di-wilcoxon-per-i-dati-non-normali\/\"><strong>Wilcoxon test<\/strong><\/a>, the <a href=\"https:\/\/www.gironi.it\/blog\/regressione-lineare-semplice\/#il-coefficiente-di-correlazione-per-ranghi-rho-di-spearman-e-un-accenno-al-tau-di-kendall\" data-type=\"post\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Spearman rank correlation coefficient<\/strong><\/a>, and the <a href=\"https:\/\/www.gironi.it\/blog\/regressione-lineare-semplice\/#il-coefficiente-di-correlazione-per-ranghi-rho-di-spearman-e-un-accenno-al-tau-di-kendall\" data-type=\"post\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Kendall rank correlation coefficient<\/strong><\/a>.<\/p>   <h2 class=\"wp-block-heading\">General Considerations<\/h2>   <p>Generally, parametric tests are more powerful than non-parametric tests, but they require data to meet certain conditions. When these conditions are not met, non-parametric tests provide a viable alternative.<\/p>   <p>Additionally, it is important to note that non-parametric tests can sometimes be used even when data meet the requirements for parametric tests; in such cases, they are often chosen for greater robustness or to avoid making overly restrictive assumptions.<\/p> ","protected":false},"excerpt":{"rendered":"<p>Statistical tests can be either parametric or non-parametric. Parametric Tests: The Power of Normality These tests have a higher statistical power because they provide a greater probability of correctly rejecting a false statistical hypothesis.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[161],"tags":[1232,1230],"class_list":["post-3309","post","type-post","status-publish","format-standard","hentry","category-statistics","tag-non-parametric-tests","tag-parametric-tests"],"lang":"en","translations":{"en":3309,"it":2306},"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"post-thumbnail":false},"uagb_author_info":{"display_name":"paolo","author_link":"https:\/\/www.gironi.it\/blog\/author\/paolo\/"},"uagb_comment_info":3,"uagb_excerpt":"Statistical tests can be either parametric or non-parametric. Parametric Tests: The Power of Normality These tests have a higher statistical power because they provide a greater probability of correctly rejecting a false statistical hypothesis.","_links":{"self":[{"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/posts\/3309","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/comments?post=3309"}],"version-history":[{"count":1,"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/posts\/3309\/revisions"}],"predecessor-version":[{"id":3310,"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/posts\/3309\/revisions\/3310"}],"wp:attachment":[{"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/media?parent=3309"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/categories?post=3309"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.gironi.it\/blog\/wp-json\/wp\/v2\/tags?post=3309"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}