Energy And Environment Questions | Vox

Httpswwwvoxcomenergy And Environment201983020840224business

Chapter 6 Confidence Interval Estimates Learning Objectives • Define point estimate, standard error, confidence level and margin of error • Compare and contrast standard error and margin of error • Compute and interpret confidence intervals for means and proportions • Differentiate independent and matched or paired samples Learning Objectives • Compute confidence intervals for the difference in means and proportions in independent samples and for the mean difference in paired samples • Identify the appropriate confidence interval formula based on type of outcome variable and number of samples Statistical Inference • There are two broad areas of statistical inference, estimation and hypothesis testing. • Estimation, the population parameter is unknown, and sample statistics are used to generate estimates of the unknown parameter.

Statistical Inference • Hypothesis testing, an explicit statement or hypothesis is generated about the population parameter. Sample statistics are analyzed and determined to either support or reject the hypothesis about the parameter. • In both estimation and hypothesis testing, it is assumed that the sample drawn from the population is a random sample. Estimation • Process of determining likely values for unknown population parameter • Point estimate is best single-valued estimate for parameter • Confidence interval is range of values for parameter: point estimate + margin of error

Estimation A point estimate for a population parameter is the "best" single number estimate of that parameter. A confidence interval estimate is a range of values for the population parameter with a level of confidence attached (e.g., 95% confidence that the range or interval contains the parameter).

Confidence Interval Estimates point estimate + margin of error point estimate + Z SE (point estimate) where Z = value from standard normal distribution for desired confidence level and SE (point estimate) = standard error of the point estimate Confidence Intervals for m • Continuous outcome • 1 Sample n > 30 (Find Z in Table 1B) n 30 and n2>30 (Find Z in Table 1B) n1 30 (Find Z in Table 1B) n p^x (1 - p)^(n - x), where C(n, x) is the combination function.