{"id":44208,"date":"2025-06-30T14:24:10","date_gmt":"2025-06-30T14:24:10","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=44208"},"modified":"2025-06-30T14:24:11","modified_gmt":"2025-06-30T14:24:11","slug":"each-entry-in-a-table-of-random-digits-like-table-d-has-probability-0-1-of-being-aand-the-digits-are-independent-of-one-another","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/each-entry-in-a-table-of-random-digits-like-table-d-has-probability-0-1-of-being-aand-the-digits-are-independent-of-one-another\/","title":{"rendered":"Each entry in a table of random digits like Table D has probability 0.1 of being aand the digits are independent of one another."},"content":{"rendered":"\n<p><br>Each entry in a table of random digits like Table D has probability 0.1 of being a<br>and the digits are independent of one another. If many lines of 40 random digits are selected, the mean and standard deviation of the number of 0 s will be approximately (a) mean<br>standard deviation<br>. (b) mean<br>standard deviation<br>(c) mean<br>standard deviation<br>. (d) mean<br>standard deviation<br>. (e) mean<br>standard deviation<br>.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Part a) Find the probability that a group of five random digits will contain at least one 0.<\/h3>\n\n\n\n<p>Each digit in the table has a probability of 0.1 of being a 0, and 0.9 of being any other digit (1-9). We can use the complement rule to find the probability of having at least one 0 in five digits. First, we calculate the probability of having no 0s at all, and then subtract that from 1 to find the probability of having at least one 0.<\/p>\n\n\n\n<p>The probability that a single digit is <strong>not<\/strong> a 0 is 0.9. Therefore, the probability that <strong>none<\/strong> of the five digits are 0s is:P(no&nbsp;0s)=(0.9)5=0.59049P(\\text{no 0s}) = (0.9)^5 = 0.59049P(no&nbsp;0s)=(0.9)5=0.59049<\/p>\n\n\n\n<p>Thus, the probability of having at least one 0 is:P(at&nbsp;least&nbsp;one&nbsp;0)=1\u2212P(no&nbsp;0s)=1\u22120.59049=0.40951P(\\text{at least one 0}) = 1 &#8211; P(\\text{no 0s}) = 1 &#8211; 0.59049 = 0.40951P(at&nbsp;least&nbsp;one&nbsp;0)=1\u2212P(no&nbsp;0s)=1\u22120.59049=0.40951<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Part b) Find the probability that a group of five random digits will contain exactly three 0s.<\/h3>\n\n\n\n<p>This is a binomial probability problem where the number of trials is 5 (since there are 5 digits), and the probability of success (getting a 0) on each trial is 0.1. The formula for the binomial probability is:P(k&nbsp;successes)=(nk)pk(1\u2212p)n\u2212kP(k \\text{ successes}) = \\binom{n}{k} p^k (1-p)^{n-k}P(k&nbsp;successes)=(kn\u200b)pk(1\u2212p)n\u2212k<\/p>\n\n\n\n<p>where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>n=5n = 5n=5 is the number of trials,<\/li>\n\n\n\n<li>k=3k = 3k=3 is the number of successes (0s),<\/li>\n\n\n\n<li>p=0.1p = 0.1p=0.1 is the probability of success.<\/li>\n<\/ul>\n\n\n\n<p>The binomial coefficient (nk)\\binom{n}{k}(kn\u200b) is calculated as:(53)=5!3!(5\u22123)!=5\u00d742\u00d71=10\\binom{5}{3} = \\frac{5!}{3!(5-3)!} = \\frac{5 \\times 4}{2 \\times 1} = 10(35\u200b)=3!(5\u22123)!5!\u200b=2\u00d715\u00d74\u200b=10<\/p>\n\n\n\n<p>Now, calculate the probability:P(exactly&nbsp;3&nbsp;0s)=(53)(0.1)3(0.9)2=10\u00d7(0.1)3\u00d7(0.9)2P(\\text{exactly 3 0s}) = \\binom{5}{3} (0.1)^3 (0.9)^2 = 10 \\times (0.1)^3 \\times (0.9)^2P(exactly&nbsp;3&nbsp;0s)=(35\u200b)(0.1)3(0.9)2=10\u00d7(0.1)3\u00d7(0.9)2P(exactly&nbsp;3&nbsp;0s)=10\u00d70.001\u00d70.81=0.0081P(\\text{exactly 3 0s}) = 10 \\times 0.001 \\times 0.81 = 0.0081P(exactly&nbsp;3&nbsp;0s)=10\u00d70.001\u00d70.81=0.0081<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Part c) Suppose we have 40 random digits. What is the mean number of 0s in these 40 digits?<\/h3>\n\n\n\n<p>The number of 0s in 40 digits follows a binomial distribution. The mean of a binomial distribution is given by:\u03bc=n\u00d7p\\mu = n \\times p\u03bc=n\u00d7p<\/p>\n\n\n\n<p>where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>n=40n = 40n=40 is the number of trials,<\/li>\n\n\n\n<li>p=0.1p = 0.1p=0.1 is the probability of getting a 0.<\/li>\n<\/ul>\n\n\n\n<p>Thus, the mean number of 0s in 40 digits is:\u03bc=40\u00d70.1=4\\mu = 40 \\times 0.1 = 4\u03bc=40\u00d70.1=4<\/p>\n\n\n\n<p>So, on average, you can expect 4 zeros in a group of 40 random digits.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Summary of Results:<\/h3>\n\n\n\n<p>a) The probability that a group of five random digits will contain at least one 0 is 0.40951.<br>b) The probability that a group of five random digits will contain exactly three 0s is 0.0081.<br>c) The mean number of 0s in a group of 40 random digits is 4.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"852\" height=\"1024\" src=\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-1481.jpeg\" alt=\"\" class=\"wp-image-44209\" srcset=\"https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-1481.jpeg 852w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-1481-250x300.jpeg 250w, https:\/\/gaviki.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-1481-768x923.jpeg 768w\" sizes=\"auto, (max-width: 852px) 100vw, 852px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Each entry in a table of random digits like Table D has probability 0.1 of being aand the digits are independent of one another. If many lines of 40 random digits are selected, the mean and standard deviation of the number of 0 s will be approximately (a) meanstandard deviation. (b) meanstandard deviation(c) meanstandard deviation. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-44208","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/44208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=44208"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/44208\/revisions"}],"predecessor-version":[{"id":44210,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/44208\/revisions\/44210"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=44208"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=44208"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=44208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}