Otherwise, use a z-score. Take the square root of the calculated value. Advertisement Autoplay When autoplay is enabled, a suggested video will automatically play next. Find the critical value.

Mathispower4u 54,007 views 5:15 Margin of Error Sample Size TI-83+ - Duration: 11:16. When working with and reporting results about data, always remember what the units are. In general, for small sample sizes (under 30) or when you don't know the population standard deviation, use a t-score. Find a Critical Value 7.

Check out our Youtube channel for video tips on statistics! To be 99% confident, you add and subtract 2.58 standard errors. (This assumes a normal distribution on large n; standard deviation known.) However, if you use a larger confidence percentage, then drenniemath 37,192 views 11:04 Confidence Intervals Part I - Duration: 27:18. Add to Want to watch this again later?

t-test - Duration: 8:08. Copyright © 2016 Statistics How To Theme by: Theme Horse Powered by: WordPress Back to Top Toggle navigation Search Submit San Francisco, CA Brr, itÂ´s cold outside Learn by category LiveConsumer statisticsfun 65,179 views 6:46 How to use Excel to Calculate Confidence Interval - Duration: 4:59. Refer to the above table for the appropriate z*-value.

A sample proportion is the decimal version of the sample percentage. Two conditions need to be met in order to use a z*-value in the formula for the margin of error for a sample proportion: You need to be sure that is Vanessa Graulich 108,846 views 3:21 Margin of Error - Duration: 6:17. mathwithmrbarnes 318,470 views 9:03 Compute 95% Confidence Interval.mp4 - Duration: 4:14.

The choice of t statistic versus z-score does not make much practical difference when the sample size is very large. Solution The correct answer is (B). The number of standard errors you have to add or subtract to get the MOE depends on how confident you want to be in your results (this is called your confidence Easy!

AGodboldMath 41,466 views 10:11 Confidence Interval for a Population Proportion - Duration: 5:06. SOLUTION: 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: _____ Algebra-> Probability-and-statistics -> SOLUTION: Otherwise, use the second equation. Leave a Reply Cancel reply Your email address will not be published.

The critical t statistic (t*) is the t statistic having degrees of freedom equal to DF and a cumulative probability equal to the critical probability (p*). Here are the steps for calculating the margin of error for a sample mean: Find the population standard deviation and the sample size, n. Z Score 5. statisticsfun 43,177 views 8:04 How to calculate Confidence Intervals and Margin of Error - Duration: 6:44.

Among survey participants, the mean grade-point average (GPA) was 2.7, and the standard deviation was 0.4. In general, the sample size, n, should be above about 30 in order for the Central Limit Theorem to be applicable. The 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 As a rough guide, many statisticians say that a sample size of 30 is large enough when the population distribution is bell-shaped.

Stats 160 Final Review #1 - Duration: 1:41. Statisticshowto.com Apply for $2000 in Scholarship Money As part of our commitment to education, we're giving away $2000 in scholarships to StatisticsHowTo.com visitors. Your email Submit RELATED ARTICLES How to Calculate the Margin of Error for a Sample… Statistics Essentials For Dummies Statistics For Dummies, 2nd Edition SPSS Statistics for Dummies, 3rd Edition Statistics Since we don't know the population standard deviation, we'll express the critical value as a t statistic.

mathwithmrbarnes 318,470 views 9:03 How to find the z-score and the area of the normal distribution with the ti-84 - Duration: 5:13. mcstutoringstats 64,170 views 1:41 How to calculate margin of error and standard deviation - Duration: 6:42. Tests in a sample of 200 Centre County Pennsylvania homes found 127 (63.5%) of these sampled households to have indoor radon levels above 4 pCi/L. We will describe those computations as they come up.

If the sample size is large, use the z-score. (The central limit theorem provides a useful basis for determining whether a sample is "large".) If the sample size is small, use Click here for a short video on how to calculate the standard error. Confidence Intervals - Finding Sample Size - Duration: 8:46. Typically, you want to be about 95% confident, so the basic rule is to add or subtract about 2 standard errors (1.96, to be exact) to get the MOE (you get