{"id":156,"date":"2013-06-11T19:32:17","date_gmt":"2013-06-11T23:32:17","guid":{"rendered":"https:\/\/sites.nicholas.duke.edu\/statsreview\/?page_id=156"},"modified":"2018-05-22T13:22:17","modified_gmt":"2018-05-22T17:22:17","slug":"rounding","status":"publish","type":"page","link":"https:\/\/sites.nicholas.duke.edu\/statsreview\/math\/rounding\/","title":{"rendered":"Basic Math: Rounding and Significant Digits"},"content":{"rendered":"

In both descriptive and inferential statistics, statisticians report numbers, both in tables and in prose.\u00a0 Typically, when we report measurements or calculations we must round our numbers.\u00a0 In rounding, we are often guided by the concept of significant digits:\u00a0 the number of digits starting at the first non-zero digit and counting to the right. For example, the number 456 has three significant digits, while 456.00 has five.\u00a0\u00a0 The waters become a bit muddy when we are dealing with large whole numbers such as 13,000.\u00a0 13,000 may have two significant digits or it may have five.\u00a0 13,000.0\u00a0 suggests six significant digits.\u00a0 To clarify, scientific notation is often used:\u00a0 13,000 may be represented by 1.3 E4 or 1.3*104<\/sup>.<\/h3>\n

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How we round often depends on the precision of\u00a0 the data we collect.\u00a0 For example, if we measure the width of a blue crab, we could measure her 10 cm, 10.1 cm, 10.12 cm, etc.\u00a0 Let’s say that our caliper only allows us to measure to the 1\/10th of a centimeter and we need to calculate a mean width of ten blue crabs.\u00a0 Would it be appropriate to the report the mean as 10.3748 cm?\u00a0 No, as this would be reporting a mean that is falsely precise.\u00a0 One frequently used rule of thumb is to round a mean (or a standard deviation) to one additional decimal than the data. \u00a0So in our case, we would report the mean width of the ten crabs to be 10.37cm.<\/h3>\n

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Go to the page on Exponents<\/a>!<\/h2>\n

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Return to the Basic Math Main Webpage<\/a>.<\/h2>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

In both descriptive and inferential statistics, statisticians report numbers, both in tables and in prose.\u00a0 Typically, when we report measurements<\/p>\n","protected":false},"author":618,"featured_media":0,"parent":109,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","_exactmetrics_skip_tracking":false,"footnotes":""},"class_list":["post-156","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/P3SHON-2w","_links":{"self":[{"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/pages\/156","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/users\/618"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/comments?post=156"}],"version-history":[{"count":28,"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/pages\/156\/revisions"}],"predecessor-version":[{"id":9694,"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/pages\/156\/revisions\/9694"}],"up":[{"embeddable":true,"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/pages\/109"}],"wp:attachment":[{"href":"https:\/\/sites.nicholas.duke.edu\/statsreview\/wp-json\/wp\/v2\/media?parent=156"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}