STAT 1430 Study Guide - Midterm Guide: Probability Density Function, Sample Space, Stratified Sampling

• School: Ohio State University
• Department: Statistics
• Course: STAT 1430
• Professor: Rumsey

Document Summary

Data collection: two ways of collecting data: observational studies and experiments, random sample: each group of the same size has the same likelihood/chance/probability of being selected as the sample. There are two main types of random samples - simple random sample and stratified random sample. sampling procedure and the sample must represent the entire population: bias is a main concern when sampling. To avoid biased sample, we must use a: examples of biased sample: convenience, volunteer (self-selected), undercoverage, several important concepts in experimental designs: independent variables (factors); Dependent variables (responses): treatment group and control group. Two types of variables: quantitative data and categorical data; Data distribution: shape, center, skewness, and variability; Descriptive statistics: suppose we have x1, , xn observations. The sample standard deviation always has the same unit as the original data; it can never be negative; it can equal to 0; it is affected by outliers and skewness; interquartile range (iqr):