{"id":2403,"date":"2021-10-13T17:16:52","date_gmt":"2021-10-13T17:16:52","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/?post_type=chapter&#038;p=2403"},"modified":"2022-03-29T20:39:42","modified_gmt":"2022-03-29T20:39:42","slug":"introduction-to-two-population-means-with-unknown-standard-deviations","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/chapter\/introduction-to-two-population-means-with-unknown-standard-deviations\/","title":{"raw":"Introduction to Two Population Means with Unknown Standard Deviations","rendered":"Introduction to Two Population Means with Unknown Standard Deviations"},"content":{"raw":"<h2>What you\u2019ll learn to do: Conduct hypothesis tests for a difference in two population means and calculate and interpret Cohen's <em>d<\/em><\/h2>\r\n<img class=\"size-medium wp-image-2404 alignright\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/5668\/2021\/10\/13171543\/pexels-skitterphoto-9796-300x200.jpg\" alt=\"Someone's hand holding a gasoline nozzle that is in a car gas tank.\" width=\"300\" height=\"200\" \/>People from California and from New York often complain about the price of gasoline being so high. Is there a statistically significant difference in the average price of gasoline for California and New York? To answer this question, you would need to conduct a two-sample <em>t<\/em>-test for a difference in population means with unknown standard deviations. Additionally, you will learn how to calculate Cohen\u2019s <em>d<\/em>, which measures the relative strength of the differences between the means of two populations based on sample data.","rendered":"<h2>What you\u2019ll learn to do: Conduct hypothesis tests for a difference in two population means and calculate and interpret Cohen&#8217;s <em>d<\/em><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-2404 alignright\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/5668\/2021\/10\/13171543\/pexels-skitterphoto-9796-300x200.jpg\" alt=\"Someone's hand holding a gasoline nozzle that is in a car gas tank.\" width=\"300\" height=\"200\" \/>People from California and from New York often complain about the price of gasoline being so high. Is there a statistically significant difference in the average price of gasoline for California and New York? To answer this question, you would need to conduct a two-sample <em>t<\/em>-test for a difference in population means with unknown standard deviations. Additionally, you will learn how to calculate Cohen\u2019s <em>d<\/em>, which measures the relative strength of the differences between the means of two populations based on sample data.<\/p>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-2403\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Person Holding Gasoline Nozzle. <strong>Authored by<\/strong>: Skitterphoto. <strong>Provided by<\/strong>: Pexels. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/www.pexels.com\/photo\/car-refill-transportation-gas-9796\/\">https:\/\/www.pexels.com\/photo\/car-refill-transportation-gas-9796\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/about\/cc0\">CC0: No Rights Reserved<\/a><\/em><\/li><li><strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":169134,"menu_order":6,"template":"","meta":{"_candela_citation":"[{\"type\":\"original\",\"description\":\"Person Holding Gasoline Nozzle\",\"author\":\"Skitterphoto\",\"organization\":\"Pexels\",\"url\":\"https:\/\/www.pexels.com\/photo\/car-refill-transportation-gas-9796\/\",\"project\":\"\",\"license\":\"cc0\",\"license_terms\":\"\"},{\"type\":\"original\",\"description\":\"\",\"author\":\"\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-2403","chapter","type-chapter","status-publish","hentry"],"part":285,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/chapters\/2403","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/wp\/v2\/users\/169134"}],"version-history":[{"count":5,"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/chapters\/2403\/revisions"}],"predecessor-version":[{"id":3918,"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/chapters\/2403\/revisions\/3918"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/parts\/285"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/chapters\/2403\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/wp\/v2\/media?parent=2403"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/pressbooks\/v2\/chapter-type?post=2403"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/wp\/v2\/contributor?post=2403"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/introstatscorequisite\/wp-json\/wp\/v2\/license?post=2403"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}