2One-Sample ProblemA 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, 92.4Problem: To test that the population mean reading is 100, and to construct a confidence interval for this population mean.Summary: n = 12, Xbar = , S =
3Two-Sample ProblemThe 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.
7Problems to Demonstrate Testing Equality of Population Means Using T-TestConfidence Interval for the Difference of Population MeansTesting Equality of Population VariancesConfidence Interval for the Ratio of Population Variances
8Testing Equality of Means (Equal Variances) Two Sample T-Test and Confidence IntervalTwo sample T for NoFusion vs FusedN Mean StDev SE MeanNoFusionFused95% CI for mu NoFusion - mu Fused: ( -455, 45)T-Test mu NoFusion = mu Fused (vs <): T = P = DF = 16Both use Pooled StDev = 249
9Testing Equality and CI of Means (Unequal Variances) Two Sample T-Test and Confidence IntervalTwo sample T for NoFusion vs FusedN Mean StDev SE MeanNoFusionFused95% CI for mu NoFusion - mu Fused: ( -448, 38)T-Test mu NoFusion = mu Fused (vs <): T = P = DF = 15