SPSS (Statistical Package for the Social Sciences) is a proprietary cross-platform general-purpose statistical software package.

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11
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3answers
6k views

Difference between generalized linear models & generalized linear mixed models in SPSS

I am wondering what the differences are in SPSS between analyze-> generalized linear models-> generalized linear models & ...
175
votes
20answers
52k views

Python as a statistics workbench

Lots of people use a main tool like Excel or another spreadsheet, SPSS, Stata, or R for their statistics needs. They might turn to some specific package for very special needs, but a lot of things can ...
15
votes
4answers
5k views

Visualizing Likert responses using R or SPSS

I have 82 respondents in 2 groups (43 in Group A and 39 in Group B) that completed a survey of 65 Likert questions each ranging from 1 – 5 (strongly agree - strongly disagree). I therefore have a ...
8
votes
4answers
3k views

is psych::principal function still PCA when using rotation?

I have tried to reproduce some research (using PCA) from SPSS in R. In my experience, principal() function from package psych ...
6
votes
1answer
6k views

How to perform principal components analysis on binary data (using SPSS)?

I have a dataset with a large number of Yes/No responses. Can I use principal components (PCA) or any other data reduction analyses (such as factor analysis) for this type of data? Please advise how I ...
5
votes
1answer
957 views

Interaction in generalized linear model

I have 2 continuous variables as my predictors and the interaction between them, so 3 effects all together (when I center my predictors only the interaction is significant). I am using a binary logit ...
5
votes
1answer
405 views

Justification for low/high or tertiary splits in ANOVA

I have two groups of participants and they all took the same measurements. When I perform a median split on one of the measurements to test my hypothesis about an interaction, the dependent ...
28
votes
7answers
2k views

Why is “statistically significant” not enough?

I have completed my data analysis and got "statistically significant results" which is consistent with my hypothesis. However, a student in statistics told me this is a premature conclusion. Why? Is ...
20
votes
4answers
16k views

Fisher's Exact Test in contingency tables larger than 2x2

I was taught to only apply Fisher's Exact Test in contingency tables that were 2x2. Questions: Did Fisher himself ever envision this test to be used in tables larger than 2x2 (I am aware of the ...
8
votes
1answer
2k views

Best factor extraction methods, with reference to SPSS

SPSS offers several methods of factor extraction: Principal components (which isn't factor analysis at all) Unweighted least squares Generalized least squares Maximum Likelihood Principal Axis Alpha ...
3
votes
6answers
459 views

How to assess effect of intervention in one state versus another using annual case fatality rate?

I am a beginner in statistics with just basic knowledge. I have these data: cases, deaths and CFR (Case Fatality Rate-deaths per 100 cases) of a disease for 17 years (1994-2010) from 2 neighbouring ...
5
votes
2answers
180 views

Correlation between vegetation and erosion

I am wanting to find the correlation between two variables: a categorical vegetation variable (with categories 1-4) and a continuous variable of erosion (with values anywhere between 0.2 and 9). I ...
4
votes
1answer
328 views

Why is ANOVA interaction no longer significant after including a covariate?

I have initially run a 2x2x2 Anova and found some significant interaction between the independent variables. I then ran a ANCOVA where I added a covariate. I am confused with how to interpret the ...
3
votes
2answers
3k views

How to compare two time series?

I have collected temperature readings for 4 locations on a beach in Cornwall UK using data loggers. The loggers recorded temperature every 15 mins accurate to .1 of a degree (Celsius). The loggers ...
2
votes
2answers
422 views

What terms should I include in a linear regression model?

Consider the following OLS output. My question is: If you have to define a linear equation from the regression, do you then only include significant variables? If so, the equation according to the ...
2
votes
3answers
13k views

How to correlate ordinal and nominal variables in SPSS?

I have imported an Excel document in SPSS which contains around 500 entries. Three columns are defined, using Likert scales. I have substituted textual labels of these scales with numerical values ...
16
votes
3answers
13k views

When is R squared negative?

My understanding is that R squared cannot be negative as it is the square of R. However I ran a simple linear regression in SPSS with a single independent variable and a dependent variable. My SPSS ...
11
votes
5answers
2k views

Stepwise logistic regression and sampling

I am fitting a stepwise logistic regression on a set of data in SPSS. In the procedure, I am fitting my model to a random subset that is approx. 60% of the total sample, which is about 330 cases. ...
7
votes
2answers
4k views

How to test for normality in a 2x2 ANOVA?

Study Design: I showed participants some information about sea-level rise, focusing the information in different ways, both in terms of the time-scale and the magnitude of potential rise. Thus I had a ...
4
votes
2answers
2k views

Checking factor / covariate independence in ANCOVA

One of the ANCOVA assumptions, as I read it here, says that: Independent variables orthogonal to covariates. In traditional ANCOVA, the independents area assumed to be orthogonal to the factors. If ...
4
votes
2answers
2k views

Logistic Regression: Classification Tables a la SPSS in R

In SPSS output there is a pretty little classification table available when you perform a logistic regression, is the same possible with R? If so, how?
7
votes
5answers
2k views

Better Classification of default in logistic regression

Full Disclosure: This is homework. I've included a link to the dataset ( http://www.bertelsen.ca/R/logistic-regression.sav ) My goal is to maximize the prediction of loan defaulters in this data set. ...
6
votes
4answers
5k views

How to perform pooled cross-sectional time series analysis?

For 86 companies and for 103 days, I have collected (i) tweets (variable hbVol) about each company and (ii) pageviews for the corporate wikipedia page (...
3
votes
3answers
495 views

How to get pooled p-values on tests done in multiple imputed datasets?

Using Amelia in R, I obtained multiple imputed datasets. After that, I performed a repeated measures test in SPSS. Now, I want to pool test results. I know that I can use Rubin's rules (implemented ...
3
votes
2answers
2k views

Factor analysis for ordinal variables that have different categories

I have a data set that contains about 40 categorical variables that are taken as independent variables (and believed to be related to some unobservable human resource factors) and 4 categorical ...
3
votes
1answer
7k views

Inter-rater reliability using Intra-class correlation with ratings for multiple objects on multiple properties

Initial Question: I am trying to calculate inter-rater reliability. Previous researchers in this area have used intraclass correlation. SPSS has options for two-way random, mixed random and one-way ...
2
votes
2answers
2k views

Egger's test in SPSS

How can I conduct an Egger's test using SPSS17? For each study included in the meta-analysis I know effect size and sample size of patients and controls groups.
0
votes
2answers
6k views

Bonferroni adjustment in SPSS - what does it do?

first post, so go easy... I'm probably being a bit simplistic here, but from what I understand the Bonferroni post hoc test is simply when we adjust the alpha to account for inflated error when ...
5
votes
2answers
15k views

How to deal with non-binary categorical variables in logistic regression (SPSS)

I have to do binary logistic regression with a lot of independent variables. Most of them are binary, but a few of the categorical variables have more than two levels. What is the best way to deal ...
3
votes
2answers
387 views

Is it possible to conduct a regression if all variables are ordinal?

I would like to produce a regression analysis model. I have ordinal categorical data. I can use SPSS. I do not know what analysis to perform or what assumptions to check. What are the statistical ...
3
votes
2answers
467 views

BY and WITH command in mixed model SPSS

I coded a variable as 0/1 (species 1 vs. species 2). I assumed that a dichotomous independent variable can be put in the SPSS mixed model as either a "factor" (two levels) ("by") or, if coded 0/1 also ...
2
votes
3answers
2k views

“matrix is not positive definite” - even when highly correlated variables are removed

I am running a factor analysis in SPSS and get a "matrix is not positive definite" error from my correlation matrix. I've tried removing correlated variables, but I have to remove all variables down ...
1
vote
1answer
989 views

Covariate vs. factors

I have a survey problem where the dependent variable (ordinal) is in Likert-type scale (i.e. 1 to 5 from most satisfied to most dissatisfied) and two sets of independent variables. One set has 7 IVs ...
1
vote
1answer
15k views

Working with Likert scales in SPSS

I performed a survey using a Likert 1 to 5 scale (totally agree/agree/neutral/ disagree/totally disagree) on 12 questions which are split into 3 statements which the respondent places a value of ...
0
votes
0answers
57 views

Chi-square analysis

I am trying to determine association between my independent variables (categorical, nominal) and dependent variables (categorical, nominal). What other statistical analysis I can use aside from ...
15
votes
11answers
2k views

Best way to get started with and learn R

I have tried several times to "go it on my own" - but with limited success. I am a casual SPSS user and some SAS experience. Would appreciate a pointer or two from someone who has similar background ...
7
votes
3answers
6k views

Sidak or Bonferroni?

I am using a generalized linear model in SPSS to look at the differences in average number of caterpillars (non-normal, using Tweedie distribution) on 16 different species of plants. I want to run ...
4
votes
3answers
2k views

How to do post-hoc tests with logistic regression?

I looked at whether participants recycled after being subjected to a given message. There were three groups: a Control group, group A, and group B. Since my dependent measure was dichotomous ...
4
votes
2answers
2k views

How to correctly treat multiple data points per each subject

I am currently arguing with someoe on how to correctly treat data with multiple measurements for each subject. In this case data was gathered for each subject within a short time for different ...
4
votes
3answers
492 views

“Multiple response” analysis of arrest records

Background: I'm a junior researcher at an institute dealing with regional issues, particularly involving drug policy. Almost two years ago, one of our senior researchers began collecting arrest data ...
1
vote
2answers
362 views

Comparing two sets of time-series (physiological measures)

I need help in finding which statistical approach I need to use. I have two groups: G1 (disease) and control. For both groups we measured their blood level every 10 minutes: 0 to 650 min. We are ...
0
votes
1answer
255 views

Marketing Mix Modeling for sales data

I have data for 4 years with variables year, month and sales volume only. I want to find the base volume and incremental volume. I want to use Marketing Mix Modeling. Can anybody tell how to define ...
7
votes
2answers
6k views

Understanding repeated measure ANOVA assumptions for correct interpretation of SPSS output

I am investigating whether different reward conditions may affect task performance. I have data from a small study with two groups, each with n=20. I collected data on a task that involved performance ...
5
votes
3answers
2k views

Comparing logistic regression coefficients across models?

I've developed a logit model to be applied to six different sets of cross-sectional data. What I'm trying to uncover is whether there are changes in the substantive effect of a given independent ...
4
votes
1answer
493 views

What to do when a Mann-Whitney U assumption is violated?

I'm using a M-W U test to analyse some Likert scale results I have, as my data is ordinal. One of the assumptions that keeps on appearing on references is the following: "both distributions must be ...
4
votes
1answer
313 views

Different ANCOVA results in R using different functions

before my actual ANCOVA I would like to test whether there is a significant interaction between the IV and the CV as this is one assumption for ANCOVA. I found 3 different ways in R to perform an ...
2
votes
1answer
218 views

Rare event logistic regression

I have a situation in which that there are 4 cases with a condition per 1000 people surveyed (binary). I am interested in performing a logistic regression to determine the risk factors (binary). Is it ...
2
votes
1answer
3k views

Types of inverse transformations

In performing an inverse transformation to correct for skewness/kurtosis in SPSS, it asks me to choose what "type" of inverse transformation and I have no idea what the differences between these ...
2
votes
1answer
3k views

How to do meta-regression analysis with SPSS?

I have done a meta analysis and heterogeneity is too high. I am working with (even/Total) for experimental and control groups to calculate the Odds Ratio. I have done fixed-effect and random-effect ...
1
vote
0answers
177 views

Holt Winters initialization using backcasting like SPSS

I'm trying to figure out how SPSS is initializing the multiplicative Holt Winters exponential smoothing model using backcasting. Thankfully IBM roughly described their way of doing so .. very roughly. ...