# What is the difference between by and CLASS in Proc means?

## What is the difference between by and CLASS in Proc means?

The primary difference is that the BY statement computes many analyses, each on a subset of the data, whereas the CLASS statement computes a single analysis of all the data. Specifically, The BY statement repeats an analysis on every subgroup.

## What does Proc mean do in SAS?

PROC MEANS is one of the most common SAS procedure used for analyzing data. It is mainly used to calculate descriptive statistics such as mean, median, count, sum etc. It can also be used to calculate several other metrics such as percentiles, quartiles, standard deviation, variance and sample t-test.

**What are SAS classes?**

The CLASS statement names variables to be analyzed as categorical variables. The CLASS variables are one or more variables in the DATA= input data set. These variables can be either character or numeric. The formatted values of the CLASS variables determine the categorical variable levels.

### What is CLASS and model in SAS?

The CLASS statement names the classification variables to be used in the model. Typical classification variables are Treatment , Sex , Race , Group , and Replication . If you use the CLASS statement, it must appear before the MODEL statement. Classification variables can be either character or numeric.

### What is var statement in SAS?

The VAR statement identifies the analysis variables and their order in the output. If you omit the VAR statement, then PROC HPSUMMARY analyzes all numeric variables that are not listed in the other statements. When all variables are character variables, PROC SUMMARY produces a simple count of observations.

**How do you find the average value in SAS?**

The arithmetic mean is the value obtained by summing value of numeric variables and then dividing the sum with the number of variables. It is also called Average. In SAS arithmetic mean is calculated using PROC MEANS.

#### What are the basics of SAS?

SAS is an acronym for statistical analytics software. The main purpose of SAS is to retrieve, report and analyze statistical data . Each statement in SAS environment ends with a semicolon otherwise the statement will give an error message. It is a powerful tool for running SQL queries and automating user’s task through macros.

#### What are SAS procedures?

Sas Procedures is an inseparable part of SAS programming language. In the course you are going to learn a variety of procedures that performs data manipulation, statistical analysis and creation reports.

**What is SAS syntax?**

SAS syntax is the set of rules that dictate how your program must be written in order for SAS to understand it. There are some conventions of SAS syntax that new users should know before getting started.

## What are class variables in SAS?

Examples of classification variables (called CLASS variables in SAS) are gender, race, and treatment. The levels of the categorical variable are encoded in the columns of a design matrix. The columns are often called dummy variables. The design matrix is used to form the “normal equations” for least squares regression.