hypothesis testing

  1. U

    Hypothesis Testing - Obtaining T-Stats and Critical T-Values

    Dear all, I have been given the following question I don't really understand how to interpret this question. Commonly, hypothesis questions refer to one sampled variable with a given criterion. But this question just states that I must test the null hypothesis that one variable is not...
  2. C

    Defining Contrast Matrix

    Suppose I have a binary Covariate X which is defined as X = \begin{cases} 1, & \text{if treatment group} \\ 0, & \text{if placebo group} \end{cases} The model is \mathbb E[Y] = \beta_0 + \beta_1X, where Y is a continuous random variable. If X=0, then \mathbb E[Y] =...
  3. B

    Repeated t-tests or ANOVA for discerning difference between two treatments

    Hello, I am helping my sister with some statistics in her master's dissertation in behavorial/social sciences. I have studied a couple of courses on statistics/probability, but my proficiency could certainly be better. I have this book "An Introduction to Mathematical Statistics and it's...
  4. G

    Feedback on Experiment: bosses and meetings

    As my context is rather specific, I'll try to write an analogy that sounds more natural and preserves all characteristics of the original problem. It goes like this: A certain company has around 2k employees. Some of these employees are bosses of other employees. An employee might have...
  5. S

    Hypothesis testing with predefined constant means

    Hi, How can I calculate the p-value (statistical significance) if my hypothesis asks for specific mean values? (Cross-Post with no answer yet: ANOVA test mean against predefined constant) I suppose this can be somehow calculated using ANOVA, but I could only find examples where the hypothesis...
  6. Q

    Hypothesis Testing Help

    Hello fellow statisticians! it's been awhile since I've done stats and everything has completely escaped me. I'm trying to conduct hypothesis testing for the question below. Everyone has been using the Chi-squared test and I feel that they are wrong. I think it should be a poisson distribution...
  7. I

    Quick Question on Hypothesis Testing

    Let's say you test hypothesis at alpha=.05, does that mean that 5% of your rejections will be wrong? Is this statement true? If not, can you give an example? I know that alpha= P(type 1 error), which is the probability of rejecting given Null is true. But I still can't tell whether that...
  8. R

    How to check whethere there is a difference between 5 samples means

    I have five samples with their means (60, 58, 61.5, 48 and 42) and standard deviations (1, 3, 1.5, 4 and 2) for 3 trials. How to check whether there is a significant difference between these values by statistically.
  9. S

    Comparing regression equations

    Hello! I have a question about how to compare regression equations and regression coefficients. I have data set A with n data points, and two possible predictor data sets, X and Y, that cannot be combined in one equation, i.e., X is one way of explaining A, and Y is a different way. My...
  10. A

    help!! I have a test and none of this makes sense.

    Hello! I have an exam on inferential statistics, etc and need serious help.
  11. X

    Urgent: Hypothesis Testing with unknown standard deviation

    Hi, I'm having a lot of trouble figuring out this problem without knowing the standard deviation. Please if anyone could help me that would be very much appreciated. Thank you! I also don't know how to calculate anything other than a 95% confidence interval. A national survey conducted in...
  12. S

    Sample Mean and Standard Deviation affects results to support reject Null Hypothesis

    Hi All, I'm pretty new to Hypothesis Testing and I've come across a question I'm not sure of and was hoping someone could explain it. Suppose we wish to test H0: µ = 15 , HA: µ ≠15. Which of the following possible sample results give the most evidence to support HA? And the options...
  13. G

    Hypothesis Test method Query

    What would be the appropriate statistical method to investigate whether patients who had a history of having drug “X” on a regular basis had significantly different systolic blood pressure (SBP), diastolic blood pressure (DBP) and cholesterol level (CHL) comparedto that for patients without...
  14. A

    How to find weber fractions from a confusion matrix

    I have a confusion matrix for a 4 class classification problem which looks this: My hypothesis is that group 3 is easiest to classify. Somebody suggested me that I can find weber fractions from this confusion matrix and perform further statistical analysis. I am unable to understand how I...
  15. H

    Find xbar - Hypothesis Testing

    I have a question I'm stuck on: You are given the following hypotheses: Ho: m = 34, Ha: m > 34 sd = 10 n = 65 What would the sample mean be for the p-value to be .05 We're on the chapter dealing with hypothesis testing, so I know I should be able to find the answer in here...
  16. K

    How do you know if you're making a Type I or Type II error?

    Type I and II errors seem really theoretical. In real life, how would you ever know if you're making a Type I or Type II error? Can anyone provide any practical examples of where someone doing social science research has found out they've committed one of the two errors?
  17. A

    Likelihood Ratio test

    I have a pdf where I would like to test for the following hypothesis: H0: θ1=θ1,0; Ha: θ1>θ1,0, and f(x) =(1/θ1) exp((-x-θ2)/θ1), if x>θ2, and 0 otherwise, with θ2 unknown. I constructed the likelihood function: L(x|θ1,θ2) = (1/θ1)^n*exp(∑(i=1 to n)((-xi-θ2)/θ1) and the log likelihood...
  18. S

    Correlation Hypotheses (Pearsons) - Is a Null Hypothesis necessary?!

    Hi :) I'm quite confused on whether it is possible predicting 3 positive correlations? Or is it necessary that there should be a null? For instance, these are my hypotheses below: H1: There will be a significant positive relationship between the Mean Reaction Time on the Emotional Stroop...
  19. W

    Someone please help me with these hypothesis testing questiong!!!

    Hi Everyone, I've got an extra credit for my statistic for social science/psychology, and I've barely hitting the mark to get a pass. So I was given extra credit questions. but I don't really know how to do them. Hope someone could really help me on this! Thanks![/ATTACH]
  20. U

    Verify That I'm conducting the correct tests?

    Both problems relate to this regression model: y = b0 + B1*(x1) + B2*(x2) + e a. Does x2 have influence on y? Test: Ho: B2 = 0 Ha: B2 ≠ 0. Using a T-test between y and B2 Or use F-test and look at B2 Coeff? b. Every 10 increase in x1 corresponds to a y increase of 15? Test: Ho...