1. O

    Calculating probability given mean and standard deviation

    Hi I have looked around for this post on the forum but could not find one and have spent a while attempting this question: Given that X is normally distributed with mean 100 and standard deviation 9 and given a sample size of 16, compute the following: 1) mean and variance of X-dash 2)...
  2. M

    Mixed ANOVA: p-Value of within factor increases by adding a between factor...?

    Hello, I thought I'm good in math and statistics but this one is giving me a real headache...hope one of the pros here can explain/solve it... I ran a mixed ANOVA with one within and one between factor, both variables have 2 outcomes - pretty easy. Accidentally when I first did it, I...
  3. K

    Using multiple P-values

    I have a number of p-values from permutation tests I've done on my data. One p-value for each recording. Can I compile these values to test for overall significance?
  4. K

    HELP!!! Chi-Square Tests

    What is the difference between Homogeneity of proportions across two or more groups, Test of independence, and Goodness of fit test? Also, how would you know which test was used if all you are given is X-squared=31.3695, df=2, p-value=1.542e-07? And based on those outputs, how do you...
  5. J

    Gene expression analysis - FDR and p-values

    Hi, I'm using Affymetrix microarrays to check if there exist some differences in the gene expression of two group of animals that have been differently treated. I'm using a t-test with permutations (as my groups only have three animals and I read that it is better to use permutation if you...
  6. M

    Interpreting a paired t-test for price means

    Hey everyone, I am new to this, but I would be extremly thankful, if someone could help me with this. I research the topic of rate parity for hotels in Germany, which involves comparing rate means for different distribution channels. I have performed a paired t-test for the "phone rate...
  7. P

    QUIZ HELP: Null and Alternate Hypothesis, P-value, critical value and test statistic

    My quiz is due tomorrow and 10% of my grade. I need help doing it because I'm pretty sure I have no idea what I'm doing. The first question is A researcher claims that the average age of a woman before she has her first child is greater than the 1990 mean age of 26.2 years, on the basis...
  8. M

    how to exclude block effect (I think)

    Hi, I have done a simple experiment, with one control group and one treated group. Each group have between 3-5 replicates. The whole experiment is repeated three times. If i do a normal student t.test for each experiment i get a significant difference, however if I do a student t.test...
  9. S

    univariate test for comparison

    Hi, currently i'm testing a tree-based algorithm based on permutation tests (doesn't really matter for the question) for a paper. For every variable (100 in my simulation) I get a p-value based on the null hypothesis of independence between the variable and the response Y. Now I should...
  10. P

    Fitting distribution - Chi Square Test

    Hi, I'm need to test some data for my masterthesis. I'm a newbie to statistics, so please forgive any stupid errors I may have done. I use R for all calculations. I have set of 900000 discrete data points in the range from 1 to 600. I wanna fit a distribution to that data set. I think it is a...
  11. R

    Hypothesis testing: P-value method

    A survey claims that 9 out of 10 doctors recommend Aspirin for their patients who have children. To test this claim against an alternative that the actual proportion of doctors who would do this is less than the claimed, a random sample of 100 doctors was considered. In this sample 83 doctors...
  12. L

    Need help to test the significance

    I want to make a test to see if the difference is significant or not. What I have is two different groups of values (one with 31 values and the other with 28 values). These values have nothing to do with each other, (since it is values of iron intake for people in two different cities). I need...
  13. C

    Low correlation, but significative p-value

    Hello, I have a sample n=522, and did a spearman correlation with the result coeffeciente 0,27 **, wich indicates that there isnt a relation. However the p-valu is <0,05. My sample has a several 0 wich i belevie is the awnser to this results. Is it true? What can i think of this...