AP统计学公开课重难点专场第四场.pdf

AP统计学公开课重难点专场第四场 主讲：云舟-APstat-桂老师 AP-stat(统计) 课程地址：/course/5246347173 声音检测 •感觉声音很流畅的同学打1 •感觉声音不流畅的同学打0 版权归云舟所有 2013-3-10 1 AP Statistics 4 ：estimation 云舟国际课程中心 统计组 桂耀老师 Email:406891530@ 人人网主页：/359950110 版权归云舟所有 2013-3-10 2 Statistical Inference  A. Estimation  B. Tests of significance 3 A. Estimation  Estimating population parameters and margins of error We use a statistic as an estimate of aparameter , and generate a range of likely population values for the parameter.  Logic of confidence intervals, meaning of confidence level and confidence intervals, and properties of confidence intervals A confidence interval is composed of two parts: an estimate of a population value and a margin of error . We identify confidence intervals by how confident we are that they contain the true population value. Confidence level is the percentage of samples that would pinpoint the unknown p or μwithin plus or minus a certain margin or error. For a given sample proportion or mean, p or μeither is or isn’t within the specified. 4 A. Estimation  Properties of point estimators, including unbiasedness and variability The easiest way to estimate to unknown parameter is to use the value obtained from the sample. This statistic is called a point estimate . Point estimates are very useful if they are unbiased, or if they do not systematically tend to overestimate or underestimate the value of the true parameter.