{"id":1560,"date":"2019-10-01T13:29:00","date_gmt":"2019-10-01T13:29:00","guid":{"rendered":"https:\/\/analystprep.com\/cfa-level-1-exam\/?p=1560"},"modified":"2026-03-30T09:08:02","modified_gmt":"2026-03-30T09:08:02","slug":"sampling-error","status":"publish","type":"post","link":"https:\/\/analystprep.com\/cfa-level-1-exam\/quantitative-methods\/sampling-error\/","title":{"rendered":"Sampling Error"},"content":{"rendered":"\n<script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"VideoObject\",\n  \"name\": \"Sampling and Estimation (2021 Level I CFA\u00ae Exam \u2013 Reading 10)\",\n  \"description\": \"This video lesson covers CFA Level 1 Sampling and Estimation concepts, including random and stratified sampling, sampling error, time series vs. cross-sectional data, central limit theorem, standard error, point estimators, t-distribution, confidence intervals, and common sampling biases such as data mining, survivorship bias, and look-ahead bias.\",\n  \"uploadDate\": \"2019-12-18T00:00:00+00:00\",\n  \"thumbnailUrl\": \"https:\/\/img.youtube.com\/vi\/mgY_3CHHYBw\/maxresdefault.jpg\",\n  \"contentUrl\": \"https:\/\/www.youtube.com\/watch?v=mgY_3CHHYBw\",\n  \"embedUrl\": \"https:\/\/www.youtube.com\/embed\/mgY_3CHHYBw\",\n  \"duration\": \"PT32M00S\"\n}\n<\/script>\n\n\n\n<iframe loading=\"lazy\" width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/mgY_3CHHYBw?si=Gv2anewSMWTS45NV\" title=\"YouTube video player\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n\n\n<p>Sampling error is the statistical error that occurs when an analyst selects a sample that is <em><strong>not<\/strong> <\/em>representative of the population as a whole. In other words, it is the difference between the observed value of a sample statistic (mean, variance, or standard deviation) and the actual but unknown population parameter. For example, we calculate the sampling error for variance as:<\/p>\n<p><!--more--><\/p>\n<p>$$ \\text{Sampling error for the variance} = \\text{sample variance} \u2013 \\text{population variance} = s^2\u00a0\u2013 \\sigma^2 $$<\/p>\n<h2><strong>A Breakdown of Sampling Error<\/strong><\/h2>\n<p>A sampling exercise that involves the selection of a few elements to represent an entire population is always susceptible to both sampling errors and non-sampling errors. While sampling errors result from the data collection process, non-sampling errors are unrelated to the sample and are systematic. A good example of a non-sampling error, for instance, during the administration of a questionnaire, would manifest in the form of asking \u201cleading\u201d questions or phrasing the question in a manner that dictates the respondent to give a particular response.<\/p>\n<h3><strong>Example: Sampling Error<\/strong><\/h3>\n<p>Let\u2019s take a look at an example of sampling error in practice. We shall assume that the producers of a particular Mexican Soap Opera that airs biweekly wish to determine the percentage of Mexican viewers who watch the two episodes of the program every week. The producers would have to come up with a sample that\u2019s representative of the various classes of viewers. Among others, they will consider such factors as age. For instance, young people between the ages of 14 and 18 generally have fewer engagements, and most of them would easily manage to make time for the two weekly episodes.<\/p>\n<p>On the other hand, viewers in higher age brackets, for instance, between 18 and 35 years, may not watch the soap as often because they are more likely to have tighter working schedules and other engagements that may leave them little time for TV. Therefore, a sample drawn disproportionately, without taking the age factor into account, would produce erroneous results that may not represent the actual population parameters.<\/p>\n<p>Other factors analysts consider when selecting samples for different purposes may include gender, education level, and socioeconomic status.<\/p>\n<p>The sampling error for a given sample is usually unknown since the true population parameter is also unknown. However, analysts may use analytical methods to measure the extent of variation brought about by sampling error.<\/p>","protected":false},"excerpt":{"rendered":"<p>Sampling error is the statistical error that occurs when an analyst selects a sample that is not representative of the population as a whole. In other words, it is the difference between the observed value of a sample statistic (mean,&#8230;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-1560","post","type-post","status-publish","format-standard","hentry","category-quantitative-methods","blog-post","no-post-thumbnail","animate"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Sampling Error Explained with Examples | CFA Level 1<\/title>\n<meta name=\"description\" content=\"Learn how sampling errors occur when a sample does not represent the population, affecting statistical accuracy and analysis.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link 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