standardization

  1. G

    z-score help?

    Hi, I asked 100 people to make a single rating one a 40-point scale. Half of them got a scale ranging from 10-50. The other half got a scale from 60-100. These are organized as two columns of (incomplete) data, column A and B. I'd like to compare their means using an independent-samples t-test...
  2. C

    Basic questions about pre-/post-treatment comparison and z-standardization

    Assume I have three treatment-groups, each with pre- and post-treatment measurements: set.seed(42) n <- 100 df <- tibble( group_a_pre = rnorm(n, mean=0, sd=1), group_b_pre = rnorm(n, mean=50, sd=10), group_c_pre = rnorm(n, mean=5, sd=2), group_a_post = rnorm(n, mean=0.36, sd=1.2), group_b_post...
  3. R

    How do I find percentage from two values which are coming from two different population sets that has large difference in population sizes?

    I need to find percentage from two values which are coming from two different population sets that has large difference in population sizes. They are also different in nature. I set is teachers and another set is students. I have the performance score of 10 schools. Each schools have filled...
  4. C

    Standardize one predictor variable or all predictor variables to solve multi-collinearity

    I was using a fixed-effects panel model with interaction effects when I realized that the VIF values are too high for some variables. I was advised to standardize the predictor variables to mitigate multi-collinearity. My question is that can I standardize just 1 predictor variable or must I...
  5. H

    Can it be useful to standardize the observations over the entire dataset even when the units are the same?

    Normally when we standardize the different data points to compare the different data on the same scale. But does it also make sense to standardize data points even when the different data points are already on the same scale? For example, suppose that I have a dataset {x, y, z}, where x, y...
  6. K

    Standardizing coefficients of Logistic Regression Model

    While I'm trying to interpret and use coefficients of Logistic Regression Model, there are two set of problems that I'm facing Standardizing and bringing to a common scale, all the coefficients? Handling both negative and positive coefficients even after standardization? To explain with an...
  7. I

    Can I treat two different outcome measures as equal once standardised, even if they apply to different life-domains?

    I am about to launch an online study on the topics of self-control and goal-directed behaviour. To briefly provide an overview of the elements of my study that are relevant for this particular question (thus: this is not the complete design of the study): Monday: pp constitute a personal goal...
  8. D

    Standardizing Performance (sports-related)

    Hi everyone, I coach a hockey team and we collect a lot of data on our performance. While I'm reasonably numerate, my statistics skills are limited to pretty basic things. So here's my problem. We collect data each game which feeds into a process measure that provides insight into how our team...
  9. J

    Standardizing logistic regression betas in NHANES

    Hi everyone, New user here. I have a logistic regression problem in which I need to compare beta weights across variables in the analysis. I am using NHANES, which of course has a complex sampling design. Rather than using PROC LOGISTIC in SAS, I had to use PROC SURVEYLOGISTIC. I am aware...
  10. A

    Comparison of regression coefficients between (nested) geographic regions

    Hi All, I would like to compare the effect of an explanatory variable (say X1) on a response variable (Say Y) between two geographic regions in which one is a sub-region of the other. For example, I am fitting two regression models(Y on X1), one for the city data and the other for country...
  11. G

    standardize by population density

    I have a variable called "number of events" for each state. It is a raw number of event that happened during a specific time frame. I was thinking I could use the population density or weighted population density to standardize the number of events across states. Is this correct? I would divide...
  12. H

    How to standardize 3 data sets in SPSS

    Hello, I'm trying to standardize 3 data sets in SPSS to increase the power of my sample to 120 subjects in total. The 3 data sets were all conducted using the same procedure but at different times and the number varies between each of the data sets (Set 1: 50 subjects, Set 2: 34 subjects, Set...
  13. L

    Direct standardization - age

    Hi I have data with 250 events during an 10-year period. I have calculated incidence rates based on the general population. I now want to standardize the annual IRs for age using a standard-population. My age groups are split in 10-yearinterval groups=9 groups. now when calculating the...
  14. J

    Do you need to standardise data before running MCA?

    I have both ordinal and categorical data and am attempting to perform a Multiple correspondence analysis. My question is if a dataset contains a presence/absence variable (0 or 1), ranked data (1-3) as well as (1-4) and categorical data, do I need to standardise the data in some way? I am aware...
  15. R

    Incidence rate in a cohort with small sample size

    I have a small cohort of people with a specific disease (n=300) and studying the incidence of a related disease (which is kind of rare and normally occur only as a subsequence of this main disease). I have longitudinal data for this cohort over 4 years and I am fine with the study design in...
  16. amsavage

    Generating standardized standard errors

    I am testing a structural equation model using Stata. I need to report standardized direct, indirect and total effects with associated standard errors (effects decomposition). While I can get the standardized effects, Std. Err. are only generated in relation to the unstandardized coefficients...
  17. T

    Check strings for identical letters and cut off not identical letters

    Dear all, i am playing around with R and try to achieve the following: The task at hand is to clear manual non standardized inputs into a database. The manual input is for the value "Modell" and represents the models of different car producers. Example Ford Focus (Where Ford is the value...
  18. B

    coefficient standardization

    Hi All, I am working on a 2nd order regression. The span of coefficient is large (say 1:10000). So the coefficients of 2nd order are very big and not in the same order of the 1st. I think it is needed to implement normalization (both coefficients and data). However, after I did the...
  19. F

    Accounting for Pre-existing differences between Control and Treatment groups

    I've got two sets of sales data. I want to compare the two groups after one has a sales program applied to it. However, the treatment group already consists of the best performing stores in the analysis. My question is, how can I normalize/standardize the data so that I can accurately...
  20. T

    Preparing the data: from scales to factors

    Hello everyone, I am currently doing the analysis of my sample. I received my instructions but I am not 100% percent sure that I am on the right track. Therefore, I wish to ask for your help. It is about how to ... let's say "summarize" my independent variables. I have two of them, and...