test statistic

  1. J

    Null Hypothesis

    One of the biggest issues facing e-retailers is the ability to turn browsers into buyers. This is measured by the conversion rate, the percentage of browsers who buy something in their visit to a site. The conversion rate for a company's website was 10.1%. The website at the company was...
  2. B

    Stats Question

  3. P

    Derivation of random variable for chi-square distribution.

    Hello all, In the chi-square distribution, how is the value of random variable derived. In the textbooks, the random variable is given directly as. 1st equation is for random variable, 2nd value is the test statistic used during inference of variance of a population. Source: Introduction to...
  4. V

    Compare the estimated model with the model with intercept-only

    The question is: How do the test to compare the estimated model with the model with intercept-only ? How can I comment on the result ? I think we need to calculate the test F... I read several notes, but I can not understand how I do . The idea is to take Null deviance and Residual Deviance...
  5. S

    Need Help With statistic work. Hypothesis testing

    Question 1 Below are the quarterly returns on investment (in £000s) of two different investment projects, which had the same initial outlay. There is a sample of 16 quarters of returns and your manager has asked you to investigate the relative performance of each project. In particular, your...
  6. D

    Bootstrapping test statistics with panel data and SUR

    As a newbie to bootstrapping, I'm having some trouble with developing with critical wald test scores for every observation in my panel dataset. I'm using a Seemingly Unrelated Regression to predict residuals, but then I'm unsure how to resample these and develop these critical wald test values...
  7. I

    Time Series Analysis Threshold Value

    I have time-series data for 0 min, 5 min, 10 min, etc. for 5000 genes. (Gene expression). I want to set a threshold value to eliminate reads that are just "noise," so that they do not contribute too much to the fold-increases/decreases that I am trying to analyze. What is a good way to...
  8. P

    Correct metodology to test observations

    Hello to all, I have two datasets of rain measurements, the first observed at the ground level, and the second estimated from satellite radar at same location (pontual data), on daily basis. You can see in attachment the two histograms. I want to check if this two datasets came from the...
  9. K

    p-value in a two-tailed hypothesis test

    how do i find the p-value of a two-tailed hypothesis test based on a large sample if I have a test staistic eqaul to 0.95
  10. R

    Test if subsample from a large population is over-represented by extreme values

    hi everyone, I want to do a statistical test for significance, but I'm having difficulty deciding which test is most suitable. I was hoping to get some help. My data: I have changes in gene expression after a pertubation, to be precise, a log2-fold change i.e. log2((expression after...
  11. L

    HELP on Statistics

    Hi All, statistics is really not for me, so please help I have 2 population of dogs one from the shelter n100 and one from a boarding kennel n100 I have 4 types of acoustic enrichment no music music 1 music 2 music 3 I am using a quality of life score of each dog after the animal...
  12. A

    Test Statistic and P-value Calculation???

    A 1995 survey indicated that 7% of the adolescents in this age group had tried marijuana. Assuming 7% was the true value in 1995, you want to perform a test to determine whether the proportion of kids in this age group that have tried marijuana has changed since 1995. Let α = 0.1. What is the...
  13. S

    New to statistics, need a few steps on solving problem

    Okay guys, as the title says, I'm pretty new to stats. Currently I am working on a problem for a college class that is giving me a lot of grief. I would greatly appreciate some input. Here it is: A sample of 65 male professors at a major four-year university produced a mean annual pay of...
  14. F

    Durbin-Watson of 1.97

    Hi there, I ran the Durbin-Watson test for my dataset. n = 744 (sample), k = 9 (variables) My result is a DW of 1.97. SPSS does not show upper and lower d in the results section, which means: I do not know if there is evidence of no autocorrelation. How can I interpret this result...
  15. L

    Bayesian model checking: a problem with Gelman's chi-squared test

    So, I foolishly tried to implement a test Gelman and his colleagues propose to determine whether observed data actually fits a model (Bayesian Data Analysis, Edition 1, p.172; or better: Gelman, Meng, Stern, 1996). If the test worked as advertised, it would be really useful--an omnibus way to...
  16. M

    What is the role of the test statistic? [I'm not talking about the p-value]

    For example when Shapiro-Wilk test shows the statistic .945, df=12, p-value=.563 I know it's 'not significant' and I retain the H0 hypothesis, but I also have to write about the test statistic (.945), so what does it mean, when is it high, when is it low, comparing to what? Regards, Chris
  17. N

    Hypothesis testing help

    Hi, I have to: Identify the null hypothesis, Ho, the alternative hypothesis H1 and either identify the sampling distribution (normal, t, chi-square) of the test statistic, or state the methods should not be used and why for the following: Claim: The population mean is 425. Sample...
  18. S

    How to "Frame Data" and what "Test statistics" to use?

    Dear talkStats community, This is my first time posting. I would like some guidance in both the framing of my data and what test statistics to use. The raw data consists of radiographic images, whether or not a specific image has any one or more of a set of 5 "signs", and a particular...