1 / 9

Review Problems

Review Problems. Stat 701: Illustrations. One-Sample Problem. A sample of 12 radon detectors of a certain type was selected, and each was exposed to 100 pCi/L of radon. The resulting readings were as follows: 105.6, 90.9, 91.2, 96.9, 96.5, 91.3, 100.1, 105.0, 99.6, 107.7, 103.3, 92.4.

cara-hayes
Download Presentation

Review Problems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Review Problems Stat 701: Illustrations

  2. One-Sample Problem A sample of 12 radon detectors of a certain type was selected, and each was exposed to 100 pCi/L of radon. The resulting readings were as follows: 105.6, 90.9, 91.2, 96.9, 96.5, 91.3, 100.1, 105.0, 99.6, 107.7, 103.3, 92.4 Problem: To test that the population mean reading is 100, and to construct a confidence interval for this population mean. Summary: n = 12, Xbar = 98.375, S = 6.1095

  3. Two-Sample Problem The deterioration of many municipal pipeline networks across the country is a growing concern. One technology proposed for pipeline rehabilitation uses a flexible liner threaded through existing pipe. The following data represents the tensile strength (psi) of liner specimens for when a certain fusion process was used and when this process was not used. The study intended to show that using the fusion process increased the mean tensile strength.

  4. Data • No Fusion: 2748, 2700, 2655, 2822, 2511, 3149, 3257, 3213, 3220, 2753 • Fused: 3027, 3356, 3359, 3297, 3125, 2910, 2889, 2902

  5. Summary of Statistics Descriptive Statistics Variable N Mean Median StDev SE Mean NoFusion 10 2902.8 2787.5 277.3 87.7 Fused 8 3108.1 3076.0 205.9 72.8

  6. Comparative BoxPlots

  7. Problems to Demonstrate • Testing Equality of Population Means Using T-Test • Confidence Interval for the Difference of Population Means • Testing Equality of Population Variances • Confidence Interval for the Ratio of Population Variances

  8. Testing Equality of Means(Equal Variances) Two Sample T-Test and Confidence Interval Two sample T for NoFusion vs Fused N Mean StDev SE Mean NoFusion 10 2903 277 88 Fused 8 3108 206 73 95% CI for mu NoFusion - mu Fused: ( -455, 45) T-Test mu NoFusion = mu Fused (vs <): T = -1.74 P = 0.050 DF = 16 Both use Pooled StDev = 249

  9. Testing Equality and CI of Means(Unequal Variances) Two Sample T-Test and Confidence Interval Two sample T for NoFusion vs Fused N Mean StDev SE Mean NoFusion 10 2903 277 88 Fused 8 3108 206 73 95% CI for mu NoFusion - mu Fused: ( -448, 38) T-Test mu NoFusion = mu Fused (vs <): T = -1.80 P = 0.046 DF = 15

More Related