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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7
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2answers
11k views

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 ...
15
votes
1answer
12k views

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 ...
38
votes
8answers
14k views

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 ...
17
votes
3answers
22k 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 & ...
13
votes
1answer
17k views

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 ...
281
votes
26answers
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 ...
39
votes
7answers
4k 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 ...
32
votes
5answers
60k 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 ...
6
votes
1answer
4k 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
2k 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 ...
17
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4answers
14k 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 ...
5
votes
2answers
9k 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 ...
5
votes
4answers
3k views

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 ...
2
votes
2answers
1k views

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 ...
25
votes
4answers
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 ...
3
votes
2answers
5k 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 ...
2
votes
1answer
8k views

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 ...
2
votes
4answers
49k 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 ...
6
votes
3answers
12k views

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 ...
1
vote
2answers
30k 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 ...
1
vote
0answers
604 views

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., & ...
11
votes
4answers
26k views

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 ...
5
votes
3answers
5k 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 ...
9
votes
5answers
3k views

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 ...
7
votes
4answers
5k 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 ...
7
votes
2answers
2k views

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 ...
4
votes
6answers
548 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 ...
10
votes
1answer
3k views

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 ...
8
votes
2answers
13k 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
2answers
386 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 ...
5
votes
1answer
483 views

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 ...
7
votes
4answers
6k views

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. ...
3
votes
1answer
5k views

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 ...
2
votes
1answer
994 views

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 ...
18
votes
3answers
18k views

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 ...
13
votes
5answers
3k 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. ...
6
votes
2answers
4k 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?
5
votes
2answers
4k 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 ...
8
votes
2answers
9k 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 ...
6
votes
2answers
6k 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 ...
8
votes
2answers
48k 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 ...
6
votes
4answers
11k 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
1answer
2k views

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 ...
2
votes
1answer
13k 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 (...
0
votes
1answer
1k 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 ...
8
votes
3answers
24k views

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!
4
votes
4answers
5k views

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 ...
4
votes
2answers
4k views

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 ...
4
votes
1answer
10k 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
5k 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.