The objective of inferential statistics is to use sample data to obtain results about the whole
In a rst step the goal is to describe an underlying population. Since the populations are described in form of models, that a
Inferential Methods for Correlation and Regression
In the chapter on Correlation and Regression Analysis tools for describing bivariate continuous
data were introduced. The sample Pearson Correlation Coecient and the sample Regression
Hypotheses test about if is not known
In this section we will introduce how to make decisions about a population mean, , when
the standard deviation is not known. In order to develop a condence interval for estimating
and a test we need to study the sa
Inferential Statistics for Proportions
Hypotheses test about a Population Proportion p
Instead of answering questions concerning a population mean, , we now want to answer
questions about a population proportion, p.
Is the proportion of voters who s
ANOVA means ANalysis Of VAriance.
The ANOVA is tool for comparing the means of more than two populations. These means can
be inuenced by dierent factors.
Example: A local school board is interested in comparing test scores on a standardized readin
Experiment, Outcomes, Sample Space
Example 1 An psychologist examined the response of people standing in line at a copying
Student volunteers approached the person rst in line and asked for permission to skip line,
Organizing and Graphing Data
Organizing and Graphing Categorical Data
After categorical data has been sampled it should be summarized to provide the following
1. Which values have been observed? (red, green, blue, brown, orange, yellow)
Statistics and Sampling Distributions
When a random sample is selected the numerical descriptive measures calculated from such a
sample are called statistics. These statistics vary or change for each dierent random sample
Read chapters 8 and 9 in the text book.
Descriptive versus Inferential Statistics
So far we assumed to have some data available and we discussed how such data should
be properly summarized. This is called descriptive statistics.
In the upcomin
Preferred way of contact: Email
Assignments: check schedule! Hand in in class! Do it yourself!
Book: All assignments are taken from the text book. This is a good source of information
and helps to do the assignments.
Instructor: Wanhua Su
STAT 151, Covers Chapter 3 from the Textbook
In the last note we talked about the shape of a distribution: bell shaped or others, unimodal or multimodal, symmetric or skewed. Now, we will discuss how to describe
Analysis of Categorical Data
The techniques presented in previous sections cover the analysis of numerical data and variables. Up to now it is left unanswered how to analyze categorical variables and data.
How to present data for cate