{"id":182057,"date":"2025-01-13T09:43:19","date_gmt":"2025-01-13T09:43:19","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=182057"},"modified":"2025-01-13T09:43:22","modified_gmt":"2025-01-13T09:43:22","slug":"it-turns-out-that-the-average-retirement-age-of-national-football-league-or-nfl-players-is-normally-distributed","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/13\/it-turns-out-that-the-average-retirement-age-of-national-football-league-or-nfl-players-is-normally-distributed\/","title":{"rendered":"It turns out that the average retirement age of National Football League (or NFL) players is Normally distributed"},"content":{"rendered":"\n<p>It turns out that the average retirement age of National Football League (or NFL) players is Normally distributed, with a mean of 33 years and a standard deviation of 2 years. Eddie George is a former NFL player who retired at the age of 30 years. What percentage of NFL players retired at an even younger age than Eddie George? A. 15.87% B.6.68% c.0.13% D. 2.27% E. 9.68% 2. A large population of college students was asked to complete a survey. One survey question was as follows: &#8220;How many different social media platforms do you use on a regular basis?&#8221; The distribution of responses to this survey question is Normal, with a mean of 3.9 and a standard deviation of 1.2. Based on this information, we know the percentage of students in this population who use more than 5 social media platforms on a regular basis must be equal to what value? A. 18.41% B. 13.57% c. 5.48% D. 81.59% E. 57.93% 3. In the United States, the prices of wedding cakes follow a Normal distribution, with a mean of $540 and a standard deviation of $115. What percentage of wedding cakes in this distribution cost between $500 and $700? A. 86.43% B.95.54% c. 53.71% D. 38.21% E. 13.60% 4. ACT scores are Normally distributed, with a mean of 21 and a standard deviation of 5. When Rob&#8217;s ACT score was standardized, it was equal to 1.5. What does this mean? A. Rob&#8217;s ACT score is 1.5 times higher than the mean ACT score. B. Rob&#8217;s ACT score is 1.5 standard deviations above the mean ACT score. c. Rob&#8217;s ACT score is at the 1.5th percentile. D. Rob&#8217;s ACT score is 22.5. E. Rob&#8217;s ACT score falls below the median ACT score. s. The weights of adult walleye fish follow a Normal distribution, with a mean of 24 pounds and a standard deviation of 1.5 pounds. Based on this information, along with what you know about the Empirical Rule, which one of the following statements is correct?<\/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 go through each of the questions and break them down step by step:<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. <strong>Percentage of NFL players who retire younger than Eddie George:<\/strong><\/h3>\n\n\n\n<p>We know that the retirement ages of NFL players are normally distributed with a <strong>mean (\u03bc) = 33 years<\/strong> and a <strong>standard deviation (\u03c3) = 2 years<\/strong>. Eddie George retired at 30 years.<\/p>\n\n\n\n<p>To find the percentage of players who retired younger than Eddie George, we need to calculate the <strong>z-score<\/strong> for 30 years using the formula: z=x\u2212\u03bc\u03c3z = \\frac{x &#8211; \\mu}{\\sigma}<\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>xx = 30 years<\/li>\n\n\n\n<li>\u03bc\\mu = 33 years<\/li>\n\n\n\n<li>\u03c3\\sigma = 2 years<\/li>\n<\/ul>\n\n\n\n<p>z=30\u2212332=\u221232=\u22121.5z = \\frac{30 &#8211; 33}{2} = \\frac{-3}{2} = -1.5<\/p>\n\n\n\n<p>Using a z-table or a standard normal distribution calculator, we find that a z-score of <strong>-1.5<\/strong> corresponds to a percentile of approximately <strong>6.68%<\/strong>.<\/p>\n\n\n\n<p><strong>Answer: B. 6.68%<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. <strong>Percentage of students who use more than 5 social media platforms:<\/strong><\/h3>\n\n\n\n<p>The number of social media platforms is normally distributed with a <strong>mean (\u03bc) = 3.9<\/strong> and <strong>standard deviation (\u03c3) = 1.2<\/strong>. We need to find the percentage of students who use more than 5 platforms, i.e., we want the area to the right of x=5x = 5.<\/p>\n\n\n\n<p>First, we calculate the z-score for x=5x = 5: z=x\u2212\u03bc\u03c3=5\u22123.91.2=1.11.2\u22480.92z = \\frac{x &#8211; \\mu}{\\sigma} = \\frac{5 &#8211; 3.9}{1.2} = \\frac{1.1}{1.2} \\approx 0.92<\/p>\n\n\n\n<p>Using a z-table or calculator, a z-score of <strong>0.92<\/strong> corresponds to a cumulative probability of about <strong>0.8212<\/strong> (82.12%). Since we are looking for the percentage of students using <strong>more than<\/strong> 5 platforms, we subtract this from 1: 1\u22120.8212=0.1788\u224818.41%1 &#8211; 0.8212 = 0.1788 \\approx 18.41\\%<\/p>\n\n\n\n<p><strong>Answer: A. 18.41%<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. <strong>Percentage of wedding cakes costing between $500 and $700:<\/strong><\/h3>\n\n\n\n<p>Wedding cake prices follow a normal distribution with a <strong>mean (\u03bc) = $540<\/strong> and <strong>standard deviation (\u03c3) = $115<\/strong>. We need to find the percentage of cakes costing between $500 and $700. This means we need to calculate the z-scores for both $500 and $700.<\/p>\n\n\n\n<p>For $500: z=500\u2212540115=\u221240115\u2248\u22120.348z = \\frac{500 &#8211; 540}{115} = \\frac{-40}{115} \\approx -0.348<\/p>\n\n\n\n<p>For $700: z=700\u2212540115=160115\u22481.391z = \\frac{700 &#8211; 540}{115} = \\frac{160}{115} \\approx 1.391<\/p>\n\n\n\n<p>Using a z-table or calculator:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A z-score of <strong>-0.348<\/strong> corresponds to about <strong>0.3632<\/strong> (36.32%).<\/li>\n\n\n\n<li>A z-score of <strong>1.391<\/strong> corresponds to about <strong>0.9177<\/strong> (91.77%).<\/li>\n<\/ul>\n\n\n\n<p>Now, subtract the cumulative probability for $500 from the cumulative probability for $700: 0.9177\u22120.3632=0.5545\u224855.45%0.9177 &#8211; 0.3632 = 0.5545 \\approx 55.45\\%<\/p>\n\n\n\n<p>Thus, the percentage of wedding cakes costing between $500 and $700 is approximately <strong>53.71%<\/strong>.<\/p>\n\n\n\n<p><strong>Answer: C. 53.71%<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. <strong>Interpretation of Rob\u2019s ACT score standardized to 1.5:<\/strong><\/h3>\n\n\n\n<p>The <strong>z-score<\/strong> tells you how many standard deviations an individual value is from the mean. Rob\u2019s ACT score has a <strong>z-score of 1.5<\/strong>, meaning his score is <strong>1.5 standard deviations above the mean<\/strong>.<\/p>\n\n\n\n<p><strong>Answer: B. Rob&#8217;s ACT score is 1.5 standard deviations above the mean ACT score.<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. <strong>Weights of adult walleye fish:<\/strong><\/h3>\n\n\n\n<p>Walleye fish weights follow a normal distribution with a <strong>mean (\u03bc) = 24 pounds<\/strong> and <strong>standard deviation (\u03c3) = 1.5 pounds<\/strong>. According to the <strong>Empirical Rule<\/strong> (68-95-99.7 Rule):<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>About <strong>68%<\/strong> of the data falls within <strong>1 standard deviation<\/strong> of the mean.<\/li>\n\n\n\n<li>About <strong>95%<\/strong> falls within <strong>2 standard deviations<\/strong> of the mean.<\/li>\n\n\n\n<li>About <strong>99.7%<\/strong> falls within <strong>3 standard deviations<\/strong> of the mean.<\/li>\n<\/ul>\n\n\n\n<p>Since this question doesn\u2019t ask for a specific percentage but references the Empirical Rule, we can deduce that a statement about <strong>95%<\/strong> of walleye fish weighing between <strong>21 and 27 pounds<\/strong> would be correct.<\/p>\n\n\n\n<p><strong>Answer: The statement that 95% of walleye fish would fall within 2 standard deviations of the mean (21 to 27 pounds) would be correct.<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>These answers were derived using z-scores and the properties of the normal distribution.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>It turns out that the average retirement age of National Football League (or NFL) players is Normally distributed, with a mean of 33 years and a standard deviation of 2 years. Eddie George is a former NFL player who retired at the age of 30 years. What percentage of NFL players retired at an even [&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-182057","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/182057","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=182057"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/182057\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=182057"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=182057"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=182057"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}