{"id":209239,"date":"2025-04-28T18:17:36","date_gmt":"2025-04-28T18:17:36","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=209239"},"modified":"2025-04-28T18:17:38","modified_gmt":"2025-04-28T18:17:38","slug":"find-the-critical-value-za-2-that-corresponds-to-the-given-confidence-level-2","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/04\/28\/find-the-critical-value-za-2-that-corresponds-to-the-given-confidence-level-2\/","title":{"rendered":"Find the critical value za\/2 that corresponds to the given confidence level"},"content":{"rendered":"\n<p>Find the critical value za\/2 that corresponds to the given confidence level.<br>80%<br>Za\/2<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\"><strong>The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n<p>Let&#8217;s solve this carefully:<\/p>\n\n\n\n<p>The confidence level given is <strong>80%<\/strong>.<\/p>\n\n\n\n<p>The critical value ( z_{\\alpha\/2} ) corresponds to the value on the standard normal distribution such that the area between (-z_{\\alpha\/2}) and (z_{\\alpha\/2}) is the confidence level. In other words, you have 80% of the distribution&#8217;s area between (-z_{\\alpha\/2}) and (z_{\\alpha\/2}), leaving 20% of the area in the two tails combined (because 100% &#8211; 80% = 20%).<\/p>\n\n\n\n<p>Since the two tails share the 20% equally, each tail has an area of:<\/p>\n\n\n\n<p>[<br>\\frac{20\\%}{2} = 10\\% = 0.10<br>]<\/p>\n\n\n\n<p>So, the area to the left of ( z_{\\alpha\/2} ) must be:<\/p>\n\n\n\n<p>[<br>1 &#8211; 0.10 = 0.90<br>]<\/p>\n\n\n\n<p>Thus, we need to find the <strong>z-score<\/strong> that corresponds to a cumulative area of <strong>0.90<\/strong>.<\/p>\n\n\n\n<p>Using a <strong>standard normal distribution table<\/strong> or a calculator, the z-score for an area of 0.90 is approximately:<\/p>\n\n\n\n<p>[<br>z_{\\alpha\/2} = 1.28<br>]<\/p>\n\n\n\n<p>\u2705 <strong>Final Answer:<\/strong><\/p>\n\n\n\n<p>[<br>z_{\\alpha\/2} = 1.28<br>]<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Detailed Explanation (300+ Words):<\/h3>\n\n\n\n<p>The concept of a <strong>critical value<\/strong> ( z_{\\alpha\/2} ) is fundamental when working with confidence intervals, particularly in statistics and inferential analysis. The critical value represents the number of standard deviations a data point is from the mean in a normal distribution. For a given confidence level, it marks the point beyond which a certain percentage of the distribution lies in the tails.<\/p>\n\n\n\n<p>In this question, the confidence level is 80%, meaning we want the middle 80% of the normal distribution to be captured between (-z_{\\alpha\/2}) and (z_{\\alpha\/2}). To find ( z_{\\alpha\/2} ), we must first determine the total area left in the two tails of the distribution, which is 100% &#8211; 80% = 20%. Since the normal distribution is symmetric, this 20% is divided equally between the left and right tails, meaning each tail has 10% of the area.<\/p>\n\n\n\n<p>To find the correct critical value, we look for the z-score that corresponds to an area of 90% (0.90) to the left of it. In a z-table (standard normal table), 0.90 corresponds approximately to a z-score of 1.28. This means 90% of the distribution lies to the left of 1.28, leaving 10% to the right, which matches the desired division of the tails.<\/p>\n\n\n\n<p>Understanding critical values like ( z_{\\alpha\/2} ) is crucial because they directly influence the width of confidence intervals. A lower confidence level (like 80%) results in a smaller critical value and a narrower confidence interval, while a higher confidence level (like 95% or 99%) leads to a larger critical value and a wider interval. This trade-off is important in research, where precision and certainty must be balanced.<\/p>\n\n\n\n<p>Thus, for an 80% confidence level, the corresponding critical value ( z_{\\alpha\/2} ) is <strong>1.28<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Find the critical value za\/2 that corresponds to the given confidence level.80%Za\/2 The correct answer and explanation is : Let&#8217;s solve this carefully: The confidence level given is 80%. The critical value ( z_{\\alpha\/2} ) corresponds to the value on the standard normal distribution such that the area between (-z_{\\alpha\/2}) and (z_{\\alpha\/2}) is the confidence [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-209239","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/209239","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=209239"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/209239\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=209239"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=209239"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=209239"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}