**Doing More with SPSS**

Today's topics

Graphs

Basic and intermediate inferential statistics

Introduction to SPSS syntax

**Graphs and Charts**

**Bar charts** summarize variables by groups and subgroups

*Simple* displays summaries by groups

Display frequencies or percents for groups [Ex: N for HSP]

Display summary statistics for a variable by groups [Ex: Mean(RDG) by HSP]

Statistical displays for a set of variables [Ex: Medians (RDG WRTG MATH)]

*Cluster* displays summaries by groups and sub-groups (clusters) [Ex: %'s
for HSP SEX]

An elaboration of simple bar charts

Bars for "missing" can be discarded in the options menu

Can use pairwise or listwise deletion

*Histograms* summarize an interval variable [Ex: SCI with normal
curve]

A normal curve can be superimposed

**Line charts** summarize by groups

*Simple* is like a simple bar chart, midpoints of bar tops are connected
[Ex: Mean(RDG--CIV)]

*Multiple* is analogous to cluster bar charts

Can get separate lines for groups or variables

Series--transpose data switches groups with variables [Ex: Mean(RDG--CIV) by
SES]

**Scatterplots** show relationships between variables

*Simple* shows the relationship between two variables [Ex: RDG w/ WRTG by
SEX]

Axes are usually interval variables

Markers can be used for separate groups

Options can fit regression lines to the total group or subgroups

Sunflowers are for marking # of hidden cases (can't be done for subgroups)

**Some other charts**

Pie, area, high-low, boxplots, control, time series

**Editing Charts**

Done in the chart editor (or in chart windows for other versions of SPSS)

Double-click on chart to open it in chart editor

Most changes are made by editing the chart, highlighting, and selecting from
menus

Depending on the type of chart being edited, different characteristics can be
changed, including:

Axis scaling and ticks

Number of intervals

Interpolation, fitting lines, reference
line

Labels, text styles, and fonts

Titles, footnotes, annotation, and legends

Frames

Fill patterns, spacing, and colors for
bars

Bar style

Marker colors, styles, and sizes

Line styles and colors

Swapping axes

Transposing data

Sizing charts

Saving charts

Save as SPSS output (.spo)

Export as a jpeg, pict, png, tiff, or bmp (not SPSS files)

Cut and paste to another application

**Editing and Saving Output**

**Output Viewer**

Click on tree in left sends you to a table on right

Double-click on table to get in edit mode

(or go to Edit menu and open/edit SPSS Pivot Table Object)

Double-click on cell you wish to change

Somewhat limited editing options for tables

Objects can be cut and pasted to other applications

**File Menu**

Tables can be saved as SPSS output files (.spo)

They can be exported as HTML or text files

**Basic Inferential Statistics**

**Correlate**: analyze relationships between variables [Ex: RDG--CIV CONCPT
MOT]

Bivariate

Pearson vs. Spearman

Significance: 1 or 2 tailed p-values

listwise or pairwise deletion

Graph: Scatterplot

**Crosstabs:** analyze differences in proportions [Ex: RACE by SES]

Chi-squared {Sum of ((O-E)2/E)}

phi and Cramer's V

Cells: observed; expected; row, column, total percents; residuals:
unstandardized

Graph: Cluster bar chart with frequencies

**Compare means:** analyze differences in means

*Paired-samples t -test* (dependent t-test) ) [Ex: RDG with WRTG
& MATH ]

Two variables

Confidence interval

Graph: Bar chart with means

2-groups

Define groups

Graph: Bar chart with means

**Intermediate Inferential Statistics-ANOVA**

**One-way factorial ANOVA**

*Compare means:* One-way ANOVA[Ex: LOCUS by RACE, with Bonferroni post-hoc
tests]

Post hoc tests show pairwise comparisons while controlling for the number of
tests being conducted

Graph: Bar chart with means

*General Linear Model:* Univariate [Ex: LOCUS by RACE]

Differences between group means (like an extension of independent t-test)

You must specify the range for the independent variable

Graph: Bar chart with means

**Repeated measures ANOVA**

*General Linear Model:* Repeated measures [Ex: RDG WRTG MATH SCI]

Differences among means for variables (like an extension of dependent t-test)

Often used for analyzing differences over time

Specify the factor name and number of levels

Define: click on variable names

Contrasts: only limited contrasts are available through menus (seldom useful)

Graph: Line chart with means

**Intermediate Inferential Statistics-Regression**

**Multiple Regression:** forming models for prediction from multiple
predictor variables

Outcome variable is usually an interval variable

Predictor variables are usually interval variables, but can include dichotomous
variables

*Linear regression* forms a linear composite of the predictor variables in
such a manner that the correlation between the composite of predictors and the
outcome variable is maximized

[Ex: WRTG from SEX LOCUS CONCPT MOT RDG]

**Using SPSS Syntax**

**Why
use syntax?**

It can save you time if you are running similar procedures repeatedly, or at
different times

SPSS syntax can be saved as a file and retrieved for future use

Some SPSS operations are not available through menus

Downside: reading manuals

**Open a syntax window**

Preferences: open a syntax window at startup and save preferences

Paste commands to a syntax window

Open a syntax file

**Pasting syntax vs. writing**

Pasting is easy, writing is not

Writing gives you options unavailable from menus, but:

You have to know SPSS syntax

You will frequently refer to SPSS manuals

Errors are commmon and not always easy to solve

**Executing syntax**

Highlight the commands you want executed, then click the right arrow button on
the menu bar

Saving syntax

Syntax window-- File-- save or save as