1. U

    Help: working on a dataset on logaritmic scale

    Hi, for a university project I currently have to analyze a dataset inherent to a cluster of stars, in which the two main variables are luminosity and temperature of each star. The main goal is to validate the normality hypothesis in both variables (usually I go with >qqnorm() + >qqline() +...
  2. helgasaraswati

    White Test For Heteroskedasticity In R Commander

    I am trying to realize the white test on my linear model with R and White Test For Heteroskedasticity In R Commander
  3. S

    Randomness testing using frequency within a block method, chi-square statistic doubt.

    The chi-squared statistic under the frequency within a block method is defined as 4M summation of (proportion of 1s in block - 0.5 ) ^2 where M is the length Of each block I understand that this follows a chi-square goodness of fit test observed-expected frequency square. But where does this 4M...
  4. S


    If you wanted your null hypothesis to be that y and x are linearly related, and your alternative to be that they are quadratic. What could you use as your null and alternative hypothesis, and how would you go about testing it?
  5. P

    Comparing two factors in five areas

    I recently compared two factors in five different areas testing diversity of one factor against another. (Diversity was made quantitative for comparison using the Simpsons Diversity index) I received a very strong positive correlation between one diversity against another and between areas with...
  6. J

    Basic Sample Sizing Question

    Hi all, I haven't done any stats for a long time, I am looking to incorporate some stats into my Ops Risk role to get a little edge. I think I am on the right track with this first little attempt but just wanted to run it by the forum for any feedback. So at work, we are starting a new...
  7. T

    What SPSS action to take?

    Hi, I have a set of data that I need to use SPSS for. I am not sure what tests I need to use to prove their is a significant difference between the two sets of data. The data I am looking at is Group 1 and Group 2 and the frequency to which they ran within a 6 week period. Group 1...
  8. S

    WANTED: statistical basis for subtest weighting

    Hello everyone, I am planning my Master thesis project in Neuropsychology and I am currently facing a statistical/mathematical challenge. Here is what it is about: Three patient groups will be administered a cognitive screenind instrument with seven subtests. Originally, the scores...
  9. U

    using statistics in mobile application testing

    i've made a simple mobile application that functions as sending a message to a contact list and when they receive the message, their android phone will ring an alarm. we were required to test its functions in each module: ex. adding contacts i've placed it under efficiency criteria which i...
  10. S

    Help! Which test do I use and how?! *very rusty graduate*

    Hi all I have been given some data and I need to do some significance testing on it. The data revolves around food types. Firstly I have been given data, about 1000 rows, of a food type with the date the food was bought and date it went off, I need to test whether after X number of days, a...
  11. A

    Compare effect of two independent variables

    Hello, I would like your help on the following: I have run a fixed effects model (in SPSS) and want to test whether the difference between two independent variables (both positively and significanly associated with dependent variable) is significant or not. Any ideas of which test...
  12. 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...