validation

  1. D

    Validate my algorithm with probability?

    Before I start I wanna say sorry. This post might a bit vague, I'm not really sure where I'm going and it's been a while since I took a stat class. I'm hoping someone can nudge me in the right direction here, kinda lost at the moment. We have an algorithm for correcting people's height - it's...
  2. M

    Assess statistical significance of two PPVs

    Assess significance of the difference between two PPVs I recently validated a medical diagnosis in order to compose a study population. To do so, we classified each patient with a diagnosis of interest as probable, possible, or unlikely case, depending on how likely we believed the diagnosis to...
  3. Y

    How to prove two methods are “similar”?

    We are testing two imaging machines. One of the machines has been validated numerous times. However, we built the new machine and we need to prove that it is similar/comparable to the validated machine. So, the machines image a certain tube and determine a physical property. With several image...
  4. J

    External Validation of Cox Model

    I have two data set (training and validation) for building and validating a Cox model. With the training data set I fitted a cox model using stepwise selection method. The significant variables in the model were the only variables included in the validation model. Is this the right...
  5. B

    Appropriate p-value correction in two cohort meta-analysis (discovery / validation)

    Dear all, I would like to request your help and opinions on a meta-analysis setup utilizing two completely independent cancer cohorts, where one acts as discovery data set, while the other is meant as validation cohort. To 'integrate' both cohorts, I would like to select genes by FDR in...
  6. A

    How to do a Validation Study?

    My professor has asked me to do a validation study but I have never done one before and don't know what methodology or statistics to use. Basically the original study took a personality assessment with 27 scales and compared it to an ADHD assessment. A stepwise regression identified six scales...
  7. I

    whole data vs training/test data

    I have time series data of about 150 sample and 8 variables. It is used to generate a interaction network, whose exact structure is not known yet. I can propose a model using two ways: First approach, use 100 variable as training (derivation) data and 50 for testing (validation) set. This...
  8. W

    Comparing Data from Value-Based Scales with Frequency-Based Scales

    I was recently asked to correlate scores between two surveys that supposedly measure similar constructs. One has a value-based scale (very like me, somewhat like me, neither like or unlike me, somewhat Unlike me, very unlike me). The other has a frequency-based scale (never, rarely, sometimes...
  9. J

    Correlating factor scores and calculating marker scale scores

    Hi, I am doing a lexical study, identifying personality factor structure of the Malay language adjectives. I have three datasets: 1) The Malay adjective checklist 2) The Big-Five Mini Marker scale 3) The 60 items HEXACO PI My research objectives are to: 1) Examine the factor...
  10. S

    How to use higher-order scale?

    Hello, I am currently working on the development and validation of a new scale. The process went well so far, and I ended up with a higher order solution (4 subscales/factors on the first level, of which 2 load on a common second-order factor). Since the two first-order factors, which share a...
  11. R

    behavioral intent

    Dear Forum, I'm looking for advice on how to validate a measure of behavioral intent. here's a simplified example: let's say that I did a study on 5 products - I sampled 100 people and asked them to state how likely they were to purchase each product. Then, each of the products...
  12. M

    help appreciated with a validation exercise

    Hello all, I would really appreciate your help with some statistical analysis (yukh! haha!) A psychometric test has been mapped onto a companies competencies. I need to validate this to make sure it safe, accurate, valid etc to use in the future. My first instinct is to go with a...
  13. S

    Can a new tool detect difference between two means with same effectiveness?

    Hi all, I have two gels of different crosslinking densities (gels A, n = 3, and gels B, n = 3). The gold standard test of substrate MODULUS detects muA = ~4 and muB = ~8. I invented a new engineering tool that calibrates the shear STIFFNESS of a sample (related to modulus through an...
  14. H

    real world predictive model validation and testing issues

    I have a real world business problem of selecting products to recommend to our contacts in an email campaign. The data set I have contains the click thrus of our products' ads on various websites and other info about the visitors of the websites that have the ads on them. Some of the variables...