Occasionally an investigator may wish to compute a confidence interval for a, the y intercept of the true regression line, or test hypotheses about a. The estimated y intercept is simply the height of the estimated line when x 0, since a b(0) a. This implies that sa the estimated standard deviation of the statistic a, results from substituting x* 0 in the formula for . The desired confidence interval is then and a test statistic is a. The article Comparison of Winter-Nocturnal Geostationary Satellite Infrared-Surface Temperature with Shelter-Height Temperature in Florida (Remote Sensing of the Environment [1983]: 313327) used the simple linear regression model to relate surface temperature as measured by a satellite (y) to actual air temperature (x) as determined from a thermocouple placed on a traversing vehicle. Selected data are given (read from a scatterplot in the article). x 2 1 0 1 2 3 4 y 3.9 2.1 2.0 1.2 0.0 1.9 0.6 x 56 7 y 2.1 1.2 3.0 Estimate the true regression line. b. Compute the estimated standard deviation sa. Carry out a test at level of significance .05 to see whether the y intercept of the true regression line differs from zero. c. Compute a 95% confidence interval for a. Does the result indicate that a 0 is plausible? Explain.

HSA 3111 CHAPTER 5 Medical Technology Introduction: Changes Triggered By Medical Technology • Heightened consumer expectations → increased demand and utilization • Many specialized services have become available in outpatient settings • Technology has fueled specialization in medicine • Specialization is held in higher...