Questions tagged [spss]

IBM SPSS Statistics is a statistical software package. Use this tag for any on-topic question that (a) involves SPSS either as a critical part of the question or expected answer and (b) is not just about how to use SPSS.

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378 votes
26 answers
135k 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 ...
157 votes
4 answers
379k views

When is R squared negative? [duplicate]

My understanding is that $R^2$ 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 output ...
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70 votes
8 answers
54k 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 ...
51 votes
7 answers
6k 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 ...
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40 votes
1 answer
54k views

Doing principal component analysis or factor analysis on binary data

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 ...
  • 401
35 votes
4 answers
99k 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 ...
  • 641
34 votes
1 answer
42k 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 ...
  • 13.8k
33 votes
5 answers
73k 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 tale ...
  • 5,653
28 votes
3 answers
66k 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 ...
  • 647
24 votes
1 answer
49k views

Methods to compute factor scores, and what is the "score coefficient" matrix in PCA or factor analysis?

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 ...
23 votes
2 answers
25k views

CHAID vs CRT (or CART)

I am running a decision tree classification using SPSS on a data set with around 20 predictors (categorical with few categories). CHAID (Chi-squared Automatic Interaction Detection) and CRT/CART (...
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23 votes
2 answers
31k views

How to cluster time series?

I have a question about cluster analysis. There are 3000 companies, which have to be clustered according to their power usage over 5 years. Each company has values for every hour during 5 years. I ...
  • 231
22 votes
1 answer
2k views

After bootstrapping regression analysis, all p-values are multiple of 0.001996

I'm running various multiple regression analyses in SPSS 27, and with those that are not bootstrapped, the p-values vary such that I do not find the same p-value twice within a regression (e.g., the p-...
  • 419
20 votes
4 answers
27k 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 ...
  • 341
19 votes
6 answers
8k views

Interpreting discrepancies between R and SPSS with exploratory factor analysis

I am a graduate student in computer science. I have been doing some exploratory factor analysis for a research project. My colleagues (who are leading the project) use SPSS, while I prefer to use R. ...
  • 528
15 votes
3 answers
27k 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 ...
  • 155
15 votes
2 answers
19k 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 ...
  • 305
15 votes
3 answers
13k 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 ...
  • 375
15 votes
3 answers
149k 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 ...
  • 1,040
15 votes
3 answers
1k views

Predicting variance of heteroscedastic data

I am trying to do a regression on heteroscedastic data where I'm trying to predict the error variances as well as the mean values in terms of a linear model. Something like this: $$\begin{align}\\ y\...
  • 151
13 votes
5 answers
5k 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. ...
  • 1,304
13 votes
5 answers
10k 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 ...
  • 493
13 votes
4 answers
12k 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 ...
  • 271
13 votes
5 answers
8k 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. ...
12 votes
3 answers
52k 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!
user avatar
12 votes
1 answer
14k 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 ...
  • 303
11 votes
2 answers
14k views

Should I report non-significant results?

I've run a Kruskal Wallis test, and for some of the questions the p value is not significant. Would I report this in the same way as if it was significant, stating the df, test statistic and p-value? ...
  • 171
11 votes
3 answers
20k views

Is it acceptable to have only two (or less) items (variables) loaded by a factor in factor analysis?

I have a set of 20 variables that I have put through factor analysis in SPSS. For purposes of the research, I need to develop 6 factors. SPSS has shown that 8 variables (out of 20) have been loaded ...
  • 119
11 votes
5 answers
6k views

Multinomial logistic regression assumptions

What are the proper assumptions of Multinomial Logistic Regression? And what are the best tests to satisfy these assumptions using SPSS 18?
  • 119
11 votes
2 answers
35k views

How do I find correlation measure between two nominal variables?

A survey was made where people chose what they use a certain smiley to represent and entered their country of origin. I have recoded the text responses to numeric. What form of analysis should be ...
11 votes
2 answers
37k views

Bonferroni correction with Pearson's correlation and linear regression

I am running stats on 5 IVs (5 personality traits, extroversion, agreeableness, conscientiousness, neuroticism, openness) against 3 DVs Attitude to PCT, Attitude to CBT, Attitude to PCT vs CBT. I also ...
  • 111
10 votes
2 answers
18k views

Applying Rubin's rule for combining multiply imputed datasets

I am hoping to pool the results of a pretty basic set of analysis performed on a multiply imputed data (e.g. multiple regression, ANOVA). Multiple imputation and the analyses have been completed in ...
  • 159
10 votes
2 answers
7k views

Differences in kurtosis definition and their interpretation

I have recently realised that there are differences in the kurtosis values provided by SPSS and Stata. See http://www.ats.ucla.edu/stat/mult_pkg/faq/general/kurtosis.htm My understanding is that the ...
10 votes
2 answers
21k 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 ...
10 votes
2 answers
24k 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 ...
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9 votes
5 answers
21k 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. ...
  • 91
9 votes
2 answers
7k 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 ...
  • 604
9 votes
5 answers
26k views

Calculating eta squared from F and df

I'm trying to compute ANOVA effect sizes from papers that provide an F value without other information. If I understand correctly, the effect size for a single-factor ANOVA is $$ \eta {2} = \frac{ss_{...
  • 540
9 votes
1 answer
4k views

Is there a standard measure of fit to validate Exploratory factor analysis?

I am modeling Exploratory Factor Analysis in R, Python, Mplus, and SPSS with maximum likelihood method and Varimax orthogonal rotation. However, each software gives different measures of fit and I am ...
9 votes
1 answer
11k views

Building a time series model using more than independent variables

I am working on a project, and I am totally new to statistics. I have sales data for last two years at week level, along with other variables like temperature, holiday (TRUE/FALSE), where holiday are ...
  • 1,097
9 votes
4 answers
10k views

Very different results of principal component analysis in SPSS and Stata after rotation

For my PhD thesis I have to do a Principal Component Analysis (PCA). I didn't find it too difficult in Stata and was happy interpreting the results (I know there is a difference between factor and ...
  • 93
9 votes
2 answers
3k views

What is the relation between singular correlation matrix and PCA?

Can anyone kindly give me some information about the statement (last sentence) at the end of below definition. What does it mean by "It can be used when a correlation matrix is singular"? This quote ...
  • 193
9 votes
2 answers
13k 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 ...
  • 417
9 votes
2 answers
3k views

Multiple imputation questions for multiple regression in SPSS

I am currently running a multiple regression model using imputed data and have a few questions. Background: Using SPSS 18. My data appears to be MAR. Listwise deletion of cases leaves me with only ...
  • 91
8 votes
2 answers
2k views

How do I test if regression slopes are statistically different?

I have a set of data that is composed of a measured parameter (dependent variable) as a function of time (independent variable), before and after an intervention event. I have calculated slope and ...
  • 81
8 votes
4 answers
640 views

Internet statistics resources suitable for psychology students doing research

I am working on a new webpage for my part-time job as a methodological/statistical consultant for (psychology) students at my university. On this website I would like to place several links to online ...
8 votes
4 answers
875 views

Learning how to use a new statistical GUI?

The question is in the header, but I would extend the context a bit. Next semester I am due to be a teaching assistant (TA) in a course in statistics, where I would need to help sociology students ...
8 votes
3 answers
14k 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 (...
  • 417
8 votes
1 answer
5k 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 ...
  • 175
8 votes
4 answers
18k views

Friedman's test is very significant, but its post hoc comparisons (SPSS) are not significant

I ran a non-parametric Friedman's test for my data in SPSS 22 and significantly rejected the null. That would mean that among the $k$ paired samples (3 in my case), there should be detected at least ...
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