# SPSS Glossary

When we're writing about SPSS or statistics in general, we often wonder if our readers really understand all the terminology we use such as variance, histogram or z scores. For those wo don't, we wrote some background tutorials on such terms. These background tutorials are listed below.

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# Glossary

## Standard Deviation – What Is It?

The standard deviation is a number that indicates how far a set of numbers lie apart. This tutorial explains what a standard deviation is in normal language along with examples. Read More

## SPSS TEMPORARY Command

In SPSS, TEMPORARY indicates that the commands that follow are temporary. Temporary commands will be undone (reversed) when a command is run that reads the data. Read More

## Assumption of Equal Intervals

The assumption of equal intervals is the assumption that all distances between adjacent answer categories are exactly equal in the repondents' perception. Read More

## Assumption of Infinity

For most statistical tests, it is quietly assumed that your sample size is less than some 10% of your population size. If this doesn't hold, some test results may be severely biased unless you use a special correction. Read More

## Frequency Distribution – What Is It?

A frequency distribution is a table listing each distinct value of some variable and the number of times it occurs in some dataset. This tutorial shows some examples of tables and charts for frequency distributions. Read More

## Histogram – What Is It?

A histogram is a chart showing frequencies for fixed width intervals of a metric variable. This tutorial explains what histograms are and demonstrates why they are useful with illustrations and examples. Read More

## Measurement Levels

Social sciences often use the concept of measurement levels: nominal, ordinal, interval and ratio. These imply which actions are (in)appropriate for different variables. They thus provide major guidelines for analyzing data. Read More

## Sampling Distribution – What is It?

A sampling distribution is the frequency distribution of a sample statistic (mean, standard deviation or other) over repeated samples. A sampling distribution tells us which outcomes we should expect, given our research hypothesis. Read More

## Target Population

A target population can be loosely defined as “the collection of objects about which we'd like to know something”. Note that the target population is usually an essential element of a research question. Sadly, the social sciences all too often fail to be explicit on what the target population for a given question is. Read More

## Z-Scores – What and Why?

Z-scores are linearly transformed data values having a mean of zero and a standard deviation of 1. Z-scores may or may not be normally distributed. Read More

## SPSS Transformation Commands

In SPSS, a transformation is a command that is not immediately carried out when you run it. Read More

It's always a good idea to open and save data files with syntax. Like so, it can be readily seen which syntax was run on which data. One could use the syntax generated by "Paste" for this but there's a much shorter and better option. Read More

## SPSS Procedures

In SPSS, a procedure is a command that reads the data and is carried out immediately after running it. Procedures can't be used within DO REPEAT, DO IF, LOOP or TEMPORARY. Read More

## Command Syntax Reference

SPSS ships with a manual called "Command Syntax Reference" (or CSR). Whenever you don't know or understand something, this should usually be the first place to look. Read More

## Concatenate (General Concept)

Concatenating two or more strings is creating a new string consisting of the characters of the first string followed by the characters of the subsequent string(s) in their original order. Read More

## Escape Sequence (General Concept)

An escape sequence is a combination of characters that has a special meaning. Read More

## Indentation (General Concept)

Indentation is the offset of some lines of code, usually by spaces or tabs. Read More

## Module (Python Concept)

In Python, a module is a text file containing Python code. Read More

## Modulus (General Concept)

The modulus is what's left of a given number after subtracting another given number from it as many times as possible. Read More

## Path (General Concept)

A path is the specification of (a file and) a folder location. An important distinction is between relative and absolutepaths. Read More

## SPSS ALTER TYPE Command

SPSS ALTER TYPE command is mainly used for converting string variables to numeric variables. However, it has other interesting applications as well. This tutorial quickly walks you through those, pointing out some pitfalls, tips and tricks along the way. Read More

## SPSS ANY Function

The ANY function is used to compare one value to a set of other values. Read More

## SPSS Datasets

An SPSS dataset is data that only exists in your computer's working memory (RAM). Changes you make to it are discarded unless it's saved as a data file. Read More

## SPSS DO IF Command

SPSS commands between DO IF ... and END IF are applied only to cases (rows of data) that satisfy one or more conditions. In many cases, however, IF is a faster way to accomplish the same results. Read More

## SPSS Error Saving Dialog Specification

Installing an SPSS Custom Dialog sometimes triggers an Error saving dialog specification. This tutorial explains why and shows how to fix it. Read More

## SPSS FORMATS Command

SPSS FORMATS command is mainly used for setting decimal places for numeric variables. FORMATS also displays SPSS date and time values properly. This tutorial will briefly demonstrate both uses. Read More

## SPSS LAG Function

In SPSS, `LAG` is a function that returns the value of a previous case. It's mostly used on data with multiple rows of data per respondent. Here it comes in handy for calculating cumulative sums or counts. Read More

## SPSS LEAVE Command

When a new variable is calculated, this calculation starts off with a `SYSTEM MISSING` value for each case. Sometimes it's desirable to use the value of the previous case as a starting point. This can be done with the `LEAVE` command. Read More

## SPSS Macros

An SPSS macro is a function defined by the user in order to automate some task(s). Read More

## SPSS RANGE Function

The SPSS RANGE function is used to evaluate whether or not values are within a given range. Test values equal to the lower or upper boundary are also within the given range. Read More

## SPSS RANK Command

SPSS RANK can be used to create a variable holding the rank numbers of the values of some other variable. RANK is also used for discretizing continuous variables into ntile groups. This tutorial walks you through the main options along with some real world examples. Read More

## SPSS RV Function

In SPSS, RV is short for random variable. It draws random values from a given probability distribution. Read More

## SPSS Scratch Variables

Scratch variables are temporary helper variables that don't show up in your data. They are often used as LOOP index variables. Read More

## SPSS System Variables

SPSS uses a handful of hidden variables for keeping track of things. Two such system variables that are very useful are \$casenum and \$time. Read More

## SPSS Unicode Mode

SPSS Unicode mode is a setting which implies that all text in SPSS is encoded as UTF-8 (Unicode Tranformation Format 8 bit). It is mostly relevant for manipulating string variables holding non English characters. Read More

## Substring (General Concept)

A substring is a subset of characters from a string. Read More

## Unicode

Unicode - what is it and how does it work? This gentle tutorial will walk you through ASCII, Unicode, UTF-8, and related topics. Read More

## Variance – What Is It?

The variance is a number that indicates how far a set of numbers lie apart. This tutorial explains the concept gently with examples and illustrations. Read More

## Xlrd (Python Module)

Xlrd is a Module that allows Python to read data from MS Excel files. This tutorial explains where to get it and how to install it. Read More