{"id":182015,"date":"2025-01-13T07:41:23","date_gmt":"2025-01-13T07:41:23","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=182015"},"modified":"2025-01-13T07:41:25","modified_gmt":"2025-01-13T07:41:25","slug":"the-average-retirement-age-of-nfl-players-is-33-years-with-a-standard-deviation-of-2-years","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/13\/the-average-retirement-age-of-nfl-players-is-33-years-with-a-standard-deviation-of-2-years\/","title":{"rendered":"The average retirement age of NFL players is 33 years with a standard deviation of 2 years"},"content":{"rendered":"\n<p>The average retirement age of NFL players is 33 years with a standard deviation of 2 years.<\/p>\n\n\n\n<p>a) Find the probability that a randomly chosen NFL player retired at over 36 years old.<\/p>\n\n\n\n<p>b) What is the probability that a randomly chosen sample of 10NFL players has average retirement age between 34 and 35 years of age?<\/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<h3 class=\"wp-block-heading\">Part (a) Finding the probability that a randomly chosen NFL player retired over 36 years old<\/h3>\n\n\n\n<p>Given:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Average retirement age (mean), (\\mu = 33)<\/li>\n\n\n\n<li>Standard deviation, (\\sigma = 2)<\/li>\n\n\n\n<li>We are asked to find the probability that a randomly chosen NFL player retired after 36 years old, i.e., (P(X > 36)).<\/li>\n<\/ul>\n\n\n\n<p>To find this probability, we will use the <strong>Z-score<\/strong> formula, which standardizes the given value:<br>[<br>Z = \\frac{X &#8211; \\mu}{\\sigma}<br>]<br>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(X = 36) (the value we are comparing against)<\/li>\n\n\n\n<li>(\\mu = 33) (the mean)<\/li>\n\n\n\n<li>(\\sigma = 2) (the standard deviation)<\/li>\n<\/ul>\n\n\n\n<p>Substituting the values:<br>[<br>Z = \\frac{36 &#8211; 33}{2} = \\frac{3}{2} = 1.5<br>]<\/p>\n\n\n\n<p>Now, we look up the Z-score value of 1.5 in the standard normal distribution table, which gives the cumulative probability up to 36 years old:<br>[<br>P(Z &lt; 1.5) \\approx 0.9332<br>]<\/p>\n\n\n\n<p>To find the probability that the player retired <em>after<\/em> 36 years old, we subtract this value from 1:<br>[<br>P(X &gt; 36) = 1 &#8211; P(Z &lt; 1.5) = 1 &#8211; 0.9332 = 0.0668<br>]<\/p>\n\n\n\n<p>So, the probability that a randomly chosen NFL player retired over 36 years old is approximately <strong>0.0668<\/strong> or <strong>6.68%<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Part (b) Finding the probability that the average retirement age of 10 randomly chosen NFL players is between 34 and 35 years old<\/h3>\n\n\n\n<p>In this case, we are dealing with a sample of 10 NFL players, so we will use the <strong>sampling distribution<\/strong> of the sample mean. The mean of the sample mean remains the same as the population mean, but the standard deviation (standard error) of the sample mean is reduced by a factor of the square root of the sample size (n).<\/p>\n\n\n\n<p>Given:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Sample size (n = 10)<\/li>\n\n\n\n<li>Population mean (\\mu = 33)<\/li>\n\n\n\n<li>Population standard deviation (\\sigma = 2)<\/li>\n<\/ul>\n\n\n\n<p>The <strong>standard error<\/strong> (SE) is:<br>[<br>SE = \\frac{\\sigma}{\\sqrt{n}} = \\frac{2}{\\sqrt{10}} \\approx 0.6325<br>]<\/p>\n\n\n\n<p>Next, we want to find the probability that the sample mean falls between 34 and 35 years. We will calculate the Z-scores for both 34 and 35 years, using the formula:<br>[<br>Z = \\frac{X &#8211; \\mu}{SE}<br>]<\/p>\n\n\n\n<p>For (X = 34):<br>[<br>Z_{34} = \\frac{34 &#8211; 33}{0.6325} \\approx 1.58<br>]<\/p>\n\n\n\n<p>For (X = 35):<br>[<br>Z_{35} = \\frac{35 &#8211; 33}{0.6325} \\approx 3.16<br>]<\/p>\n\n\n\n<p>Now, we find the cumulative probabilities for these Z-scores:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>(P(Z &lt; 1.58) \\approx 0.9429)<\/li>\n\n\n\n<li>(P(Z &lt; 3.16) \\approx 0.9992)<\/li>\n<\/ul>\n\n\n\n<p>The probability that the sample mean is between 34 and 35 years old is the difference between these two probabilities:<br>[<br>P(34 &lt; \\bar{X} &lt; 35) = P(Z &lt; 3.16) &#8211; P(Z &lt; 1.58) = 0.9992 &#8211; 0.9429 = 0.0563<br>]<\/p>\n\n\n\n<p>So, the probability that the average retirement age of 10 randomly chosen NFL players is between 34 and 35 years old is approximately <strong>0.0563<\/strong> or <strong>5.63%<\/strong>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Part (a)<\/strong>: The probability that a randomly chosen NFL player retired after 36 years old is approximately 6.68%.<\/li>\n\n\n\n<li><strong>Part (b)<\/strong>: The probability that the average retirement age of a sample of 10 NFL players is between 34 and 35 years old is approximately 5.63%.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The average retirement age of NFL players is 33 years with a standard deviation of 2 years. a) Find the probability that a randomly chosen NFL player retired at over 36 years old. b) What is the probability that a randomly chosen sample of 10NFL players has average retirement age between 34 and 35 years [&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 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