STATS 13 Chapter Notes - Chapter 2: Null Hypothesis, Standard Error, Simple Random Sample
Document Summary
Census: collecting data on the entire population. Statistic: proportion or number calculated about a sample. Parameter: the proportion (numerical summary of a variable) of the population. Histogram: graph that summarizes the distribution of a quantitative variable. Bar heights: # of observational units in a particular interval of values. Biased sampling method: statistics from different samples consistently overestimate or underestimate the population parameter of interest. Property of the sampling method not individual sample. Ex. researcher samples the first 30 students on campus. Students with lower gpas may be more likely to be sleeping in and not present on campus. Simple random sample: ensures every sample of size n is equally likely to be the sample selected from the population. Unbiased: data collected is similar to results we would find in the entire pop. Each observational unit has the same chance of being selected as every other observational unit. Average of the sample means from different samples = population mean.
