Calculating The Margin Of Error From Confidence Interval
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Confidence Level And Margin Of Error
a confidence interval, the range of values above and below the sample statistic is called the margin of error. For example, suppose we wanted to know the percentage of adults that exercise daily.
What's The Margin Of Error For This Interval
We could devise a sample design to ensure that our sample estimate will not differ from the true population value by more than, say, 5 percent (the margin of error) 90 percent of the time (the confidence level). How to Compute the Margin of Error The margin of error can be defined by either of the following equations. Margin of error = Critical value x Standard deviation find confidence level given margin of error of the statistic Margin of error = Critical value x Standard error of the statistic If you know the standard deviation of the statistic, use the first equation to compute the margin of error. Otherwise, use the second equation. Previously, we described how to compute the standard deviation and standard error. How to Find the Critical Value The critical value is a factor used to compute the margin of error. This section describes how to find the critical value, when the sampling distribution of the statistic is normal or nearly normal. The central limit theorem states that the sampling distribution of a statistic will be nearly normal, if the sample size is large enough. As a rough guide, many statisticians say that a sample size of 30 is large enough when the population distribution is bell-shaped. But if the original population is badly skewed, has multiple peaks, and/or has outliers, researchers like the sample size to be even larger. When the sampling distribution is nearly normal, the critical value can be expressed as a t score or as a z score. When the sample size is smaller, the critical value should only be expressed as a t statistic. To find
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Use The Given Confidence Interval To Find The Margin Of Error And The Sample Mean
Need to report the video? Sign in to report inappropriate content. Sign in how is margin of error calculated in polls Transcript Statistics 154,308 views 783 Like this video? Sign in to make your opinion count. Sign in 784 16 construct and interpret a 95 confidence interval Don't like this video? Sign in to make your opinion count. Sign in 17 Loading... Loading... Transcript The interactive transcript could not be loaded. Loading... Loading... Rating is available when the video http://stattrek.com/estimation/margin-of-error.aspx has been rented. This feature is not available right now. Please try again later. Uploaded on Jul 12, 2011Tutorial on how to calculate the confidence interval and margin of error (interval estimate). Include an example and some discussion on the bell curve and z scores.Like MyBookSucks on: http://www.facebook.com/PartyMoreStud...Related Videos:Z scores and Normal Tableshttp://www.youtube.com/watch?v=q5fwCl... How to Normalized Tables Used for Z scoreshttp://www.youtube.com/watch?v=dWu0KL...Playlist t tests https://www.youtube.com/watch?v=dNfpsVLaaEE for independent and dependent means.http://www.youtube.com/playlist?list=...Created by David Longstreet, Professor of the Universe, MyBookSuckshttp://www.linkedin.com/in/davidlongs... Category Education License Standard YouTube License Show more Show less Loading... Advertisement Autoplay When autoplay is enabled, a suggested video will automatically play next. Up next How to calculate Margin of Error Confidence Interval for a population proportion - Duration: 8:04. statisticsfun 42,703 views 8:04 How to calculate sample size and margin of error - Duration: 6:46. statisticsfun 64,488 views 6:46 How to use Excel to Calculate Confidence Interval - Duration: 4:59. statisticsfun 307,486 views 4:59 How to calculate z scores - Duration: 9:34. statisticsfun 48,449 views 9:34 Margin of Error Example - Duration: 11:04. drenniemath 36,919 views 11:04 Statistics Lecture 7.2: Finding Confidence Intervals for the Population Proportion - Duration: 2:24:10. Professor Leonard 42,089 views 2:24:10 How to calculate t distributions - Duration: 5:47. statisticsfun 126,125 views 5:47 How to calculate Standard Deviation and Variance - Duration: 5:05. statisticsfun 578,461 views 5:05 Margin of Error - Duration: 6:17. headlessprofessor 45,456 views 6:17 Confidence Intervals Part I - Duration: 27:18. ProfessorSerna 164,245 views 27:18 confidence intervals, margin of error, and sample size.wmv - Duration: 11:28. AmyRobinCo
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find the margin of error and the sample mean: (0.256,0.380) a.The margin of error is: _____ b.The sample mea is: _____ Log On Ad: Mathway solves algebra homework problems with step-by-step help! Algebra: Probability and statisticsSection SolversSolvers LessonsLessons Answers archiveAnswers Immediate math help from PAID TUTORS. (paid link) Click here to see ALL problems on Probability-and-statistics Question 584875: Use the confidence interval to find the margin of error and the sample mean: (0.256,0.380) a.The margin of error is: _____ b.The sample mea is: _____ Answer by jim_thompson5910(34015) (Show Source): You can put this solution on YOUR website! a) The margin of error is equal to the radius of the confidence interval or half the width of the confidence interval. Margin of Error: ME = (b-a)/2, where the confidence interval is (a,b) ME = (0.380-0.256)/2 ME = 0.062 So the margin of error is 0.062 ------------------------------------------------------- b) The sample mean is the center of the confidence interval. Note: this is assuming that this is a confidence interval for the true population mean. Sample Mean: xbar = (a+b)/2, for some confidence interval (a,b) xbar = (0.256 + 0.380)/2 xbar = 0.318 So the sample mean is 0.318