Calculating Margin Of Error In Excel
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Calculating Percent Error Excel
email Submit RELATED ARTICLES How to Calculate the Margin of Error for a Sample… Statistics Essentials calculating confidence interval excel For Dummies Statistics For Dummies, 2nd Edition SPSS Statistics for Dummies, 3rd Edition Statistics II for Dummies Load more EducationMathStatisticsHow to Calculate the Margin of Error for calculating standard deviation excel a Sample Mean How to Calculate the Margin of Error for a Sample Mean Related Book Statistics For Dummies, 2nd Edition By Deborah J. Rumsey When a research question asks you to find a statistical sample mean (or average), you need to report a margin of error, or MOE, for the sample mean. The
Calculating Sample Size Excel
general formula for the margin of error for the sample mean (assuming a certain condition is met -- see below) is is the population standard deviation, n is the sample size, and z* is the appropriate z*-value for your desired level of confidence (which you can find in the following table). z*-Values for Selected (Percentage) Confidence Levels Percentage Confidence z*-Value 80 1.28 90 1.645 95 1.96 98 2.33 99 2.58 Note that these values are taken from the standard normal (Z-) distribution. The area between each z* value and the negative of that z* value is the confidence percentage (approximately). For example, the area between z*=1.28 and z=-1.28 is approximately 0.80. This chart can be expanded to other confidence percentages as well. The chart shows only the confidence percentages most commonly used. Here are the steps for calculating the margin of error for a sample mean: Find the population standard deviation and the sample size, n. The population standard deviat
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Calculating Margin Of Error Using Confidence Interval
Statistics for Dummies, 3rd Edition Statistics II for Dummies Load more EducationMathStatisticsHow to Calculate the Margin of Error for a Sample Proportion How to Calculate the Margin of Error for http://www.dummies.com/education/math/statistics/how-to-calculate-the-margin-of-error-for-a-sample-mean/ a Sample Proportion Related Book Statistics For Dummies, 2nd Edition By Deborah J. Rumsey When you report the results of a statistical survey, you need to include the margin of error. The general formula for the margin of error for a sample proportion (if certain conditions are met) is where is the sample proportion, n is the sample size, and http://www.dummies.com/education/math/statistics/how-to-calculate-the-margin-of-error-for-a-sample-proportion/ z* is the appropriate z*-value for your desired level of confidence (from the following table). z*-Values for Selected (Percentage) Confidence Levels Percentage Confidence z*-Value 80 1.28 90 1.645 95 1.96 98 2.33 99 2.58 Note that these values are taken from the standard normal (Z-) distribution. The area between each z* value and the negative of that z* value is the confidence percentage (approximately). For example, the area between z*=1.28 and z=-1.28 is approximately 0.80. Hence this chart can be expanded to other confidence percentages as well. The chart shows only the confidence percentages most commonly used. Here are the steps for calculating the margin of error for a sample proportion: Find the sample size, n, and the sample proportion. The sample proportion is the number in the sample with the characteristic of interest, divided by n. Multiply the sample proportion by Divide the result by n. Take the square root of the calculated value. You now have the standard error, Multiply the result by the appropriate z*-value for the confidence level desired. Refer to the
test AP formulas FAQ AP study guides AP calculators Binomial Chi-square f Dist Hypergeometric Multinomial Negative binomial Normal Poisson t Dist Random numbers Probability Bayes rule Combinations/permutations Factorial Event counter Wizard Graphing Scientific Financial Calculator books AP calculator review Statistics http://stattrek.com/estimation/margin-of-error.aspx AP study guides Probability Survey sampling Excel Graphing calculators Book reviews Glossary AP practice exam http://www.excelbanter.com/showthread.php?t=286163 Problems and solutions Formulas Notation Share with Friends Margin of Error In 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. We could devise a sample design to ensure that our sample estimate margin of 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 of the statistic Margin of error = Critical value x Standard error of the statistic If you know the margin of error 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 the critical value, follow these steps. Compute alpha (α): α = 1 - (confidence level / 100) Find the critical probability (p*): p* = 1 - α/2 To express the critical value as a z score, find
visit from the selection below. Home » ExcelBanter forum » Excel Newsgroups » Excel Programming Margin of Error Formula Author Name Remember Me? Password Site Map Home Register Authors List Today's Posts Search Web Partners Search Forums Show Threads Show Posts Advanced Search Go to Page... Margin of Error Formula « Previous Thread | Next Thread » Thread Tools Display Modes #1 December 24th 03, 12:51 AM posted to microsoft.public.excel.programming Heather Rabbitt external usenet poster Posts: 2 Margin of Error Formula Hi, I'm looking for a formula in excel to give me the maximum and minimum margin of error at the 95% confidence interval for a given percentage and sample size. For example the percentage may be 50% I have a sample size of 16 and using a stat testing program (STATCHCK) I know the margin of error is +/- 25% so my maximum would be 75% and my minimum would be 25%. My problem is I have over 10,000 numbers to check and I want to automate this in excel. I know there is a data analysis add in excel but not sure if it can be used to solve my problem. Any help with my problem would be greatly appreciated. If you think this should be posted somewhere else please let me know. Thanks in advance, Heather Heather Rabbitt View Public Profile View message headers Find all posts by Heather Rabbitt Find all threads started by Heather Rabbitt Ads #2 December 24th 03, 01:37 AM posted to microsoft.public.excel.programming Tom Ogilvy external usenet poster Posts: 27,285 Margin of Error Formula the standard error for your sample percentage is = sqrt(((100-percentage)*percentage)/n-1) assume 50% is in A1, 16 in B1 = sqrt(((100%-A1)*A1)/(B1-1)) This comes out to 12.91% assuming your percentage is normally distributed, then a 95% confidence interval says you should go +/- 1.96 standard errors from the mean 50% - (1.96 * 12.91%) as the lower bound and 50% + (1.96 * 12.91%) as the upper bound (1.96 * 12.91%) = 25.303% so you lower bound formula would be = A1-1.96*sqrt(((100%-A1)*A1)/(B1-1)) your upper bound formula would be = A1+1.96*sqrt(((100%-A1)*A1)/(B1-1)) -- Regards, Tom Ogilvy Heather Rabbitt > wrote in message om... > Hi, > > I'm looking for a formula in excel to give me the maximum and minimum > margin of error at the 95% confidence interval for a given percentage > and sample size. > > For example the percentage may be 50% I have a sample size of 16 and > using a stat testing program (STATCHCK) I know the margin of error is > +/- 25% so my maximum would be 75% and my minimum would be 25%. > > My problem is I have over