145x Filetype PPTX File size 2.01 MB Source: s3-us-west-2.amazonaws.com
The Big Picture Probability Statistical inference always involves an argument based on probability. Recall the following important points about probability • Probability is a measure of how likely an event is to occur. • We can make probability statements only about random events. Random here means that the outcome is uncertain in the short run but has a predictable pattern in the long run. Inference Research Questions That Involve Inference Type of Question Examples Variable Type Unit Make an estimate about What proportion of all U.S. Categorical variable Inference for One the population adults support the death Proportion penalty? Make an estimate about What is the average Quantitative variable Inference for Means the population number of hours that community college students work each week? Test a claim about the Do the majority of Categorical variable Inference for One population community college Proportion students qualify for federal student loans? Test a claim about the Has the average birth Quantitative variable Inference for Means population weight in a town decreased from 3,500 grams? Compare two Are teenage girls more Categorical variable Inference for Two populations likely to suffer from Proportions depression than teenage boys? Compare two In community colleges do Quantitative variable Inference for Means populations female students have a higher average GPA than male students? Inference Procedure Each research question from the previous slide relates to either a categorical variable or a quantitative variable. In this course, three criteria determine the inference procedure we use: • The type of variable. • The type of inference (estimate a population value or test a claim about a population value). • The number of populations involved.
no reviews yet
Please Login to review.