# Tagged Questions

IBM SPSS Statistics (formerly SPSS, i.e. "Statistical Package for the Social Sciences") is a proprietary cross-platform general-purpose statistical software package. [For SPSS Modeler, use 'spss-modeler' tag.]

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### What is component (factor) score coefficient matrix in PCA or factor analysis and how is it calculated?

As per my understanding, in PCA based on correlations we get factor (= principal component in this instance) loadings which are nothing but the correlations between variables and factors. Now when I ...
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### Best factor extraction methods in factor analysis

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 ...
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### Is PCA followed by a rotation (such as varimax) still PCA?

I have tried to reproduce some research (using PCA) from SPSS in R. In my experience, principal() function from package psych ...
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### 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 & ...
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### Doing principal component analysis or factor 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 ...
103k 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### How to handle with missing values in order to prepare data for feature selection with LASSO?

My situation: small sample size: 116 binary outcome variable long list of explanatory variables: 44 explanatory variables did not come from the top of my head; their choice was based on the ...
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### How to select a subset of variables from my original long list in order to perform logistic regression analysis?

My situation: small sample size: 116 binary outcome variable long list of explanatory variables: 44 explanatory variables did not come from the top of my head; their choice was based on the ...
33k 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 ...
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### 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 ...
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### Hierarchical or Two-step cluster analysis for binary data?

(This question is an edited version of a question I previously posted which one user recommended would benefit from more focus). I have 2000 questionnaires from respondents which ask 33 different ...
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### 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 ...
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### My distribution is normal; Kolmogorov-Smirnov test doesn't agree

I have a problem with the normality of some data I have: I've done a Kolmogorov test which says it isn't normal with p=.0000, I don't understand: the skewness of my distribution =-.497, and the ...
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### 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 ...
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### Difference between BIRCH and Two-Step Clustering

I don't have SPSS. But judging from the documentation you can find on the internet, SPSS "Two-Step Clustering" seems to be closely related to BIRCH clustering: Zhang, T., Ramakrishnan, R., & ...
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### Difference between binomial, negative binomial and Poisson regression

I am looking for some information about the difference between binomial, negative binomial and Poisson regression and for which situations are these regression best fitted. Are there any tests I can ...
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### 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 ...
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### Multiple imputation for missing values

I would like to use imputation for replacing missing values in my data set under certain constraints. For example, I'd like the imputed variable x1 to be greater ...
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### 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 ...
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### SPSS and Stata output different

I'm Stata-proficient but learning SPSS for my new position. I am using a simple dataset to do very basic regressions and comparing to see if the results are the same. They're not. I'm close, but the ...
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### 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 ...
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### Displaying Ordinal Data - Means, Medians, and Mean Ranks

I have some ordinal data that is not normally distributed, so I decided to do non-parametric testing using the Mann-Whitney U Test. I am looking at differences between groups for seven scores - these ...
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### 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 ...
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### 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 ...
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### Non-normally distributed data - Box-Cox transformation?

I have data that is not normally distributed. The problem seems to be that there are too many of one value relative to other values. What I have tried to make data normal: I have tried a log ...
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### Is 0 a valid value in a Likert scale?

I have carried out my pilot study on language learning motivation using a 6 point Likert scale but from 0 (strongly disagree) to 5 (very much agree). I noticed a colleague in his survey used 1 to 6. ...
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### Can non normal data be used for factor analysis and multiple regression? If so what is the procedure to justify it?

While I was writing up the analysis in my thesis, I just came across when rechecking my test for normality, that the p-value for most continuous variables was .000, which is less than .05, and it ...
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### Why do coefficients and significance levels change so much in my OLS? Do I need MIXED model instead?

Please consider the following OLS model: As a rule of thumb, a VIF score of max. 5 is considered acceptable collinearity in most fields. So for the better part I believed this model to be quite ...
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### Choice between Type-I, Type-II, or Type-III ANOVA [duplicate]

We have a dataset with three variables (dV: self-reported measure on scale 1-5, assumed to be metric; iV1: factor with 4 levels; iV2: factor with 8 levels). We are interested whether the dV differs in ...
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### 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. ...
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### 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?
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 (...
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### How to follow up a factorial MANOVA with discriminant analysis?

This is a follow-up to to my previous question: How can MANOVA report a significant difference when none of the univariate ANOVAs reaches significance? I have two IVs with each having three levels ...
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### 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 (...
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### 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 ...
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### Can I use multiple regression when I have mixed categorical and continuous predictors?

It looks like you can use coding for one categorical variable, but I have two categorical and one continuous predictor variable. Can i use multiple regression for this in SPSS and if so how? thanks!
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### Unequal variances t-test or U Mann-Whitney test?

I have two independent samples and I need to compare their values, to say if values in the first group are higher than values in the second group. I performed the Levene's test and the variances are ...
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### How to test a curvilinear relationship in a logistic regression

I was looking for some information about curvilinear relationships (quadratic function, to be precise) in logistic regression online, and couldn't really find much about it. I am interested if that ...