confidence interval

  1. I

    Sample Estimate expression in Brunner-Muenzel test with R (lawstat)

    Dear Talk Stats Community, I try to provide a reasonable interpretation of Sample Estimate expression P(X<Y) + .5*P(X=Y), which is shown as an output for BM-test in R (lawstat package). I am confused with the relationship between the following three probabilities: P(X<Y), P(X>Y), P(X=Y)...
  2. T

    Minimum Accepted Sample Size for Tolerance Interval (confidence interval)

    Hi, I'm using the tolerance interval function in minitab, my sample size is limited to 7 (the parts are expensive blah blah) I've heard to be statistically significant a sample size of 30 is recommended but in practice how low can I go for sample size when using a confidence / tolerance...
  3. H

    Difference-in-differences in Health Economics Research

    Hi, I'm doing a difference-in-differences analysis of a health policy intervention. Health clinics are paid for the percentage of eligible patients who they give the right treatment to. The clinics are measured/paid separately for each type of treatment indicator. One year, some of the...
  4. V

    T-testing of two samples(question about t-statistic)

    Hi have two questions regarding an t-test assignment i did. Basically the null hypothesis was that if sample x2 differed 35 off the mean from sample x1 was it reject-able? The mean of sample x is 395 The mean of sample ý is 435. So the issue is that i think the nominator for the t-statistic...
  5. F

    Constructing intervals VS hypothesis testing?

    Hi folks, let me briefly anticipate that I am a total newby to the magical world of statistics. So, right now I'm preparing for a "quantitative methods for economics" test, but while doing my exercises I found myself wondering about what could be very stupid things. here's the thing: I had...
  6. A

    How can I find an interval estimate for the mean of a Weibull distribution?

    I have a sample of n = 75 taken from a Weibull distribution and have computed mle estimates for the scale a and shape b parameter. The mean of a Weibull distribution (2 parameter) is given as u = a^(-1/b)*gamma(1+ 1/b) In which case I can find an estimate for u by simply plugging in the mle...
  7. S

    Excel 95 % confidence interval

    Hello everybody, I am learning about data science at the moment. I want to calculate the 95% confidence interval for the amount of Long-Term Debt that I could expect to have with Long Term Assets of $50,000,000. I calculated a regression analysis for the impact of long-term assets on long-term...
  8. A

    plot mean value according to confidence interval

    Hi all, i have a very simple question, because i am not good at statistics but i need that :) I have two signals, one is lets say 'x' another is 'time', so its a time serie. I need to find the upper and lower values of my signals according to confidence interval and then show them on a graph...
  9. K

    (A Possible) Pooled P-Test Problem

    Historical data shows that 4% of the components produced at a certain manufacturing facility are defective. A particularly harsh labor dispute has recently been concluded, and management is curious about whether it will result in any change in this figure of 4%. A random sample of 500 items...
  10. K

    A simple confidence problem that I can't seem to solve

    Mr. Grumpy and Mr. Happy are both running for Governor. Mr. Grumpy will eventually win the election with 51 percent of the vote. A day before the election, a state-wide newspaper surveys 100 people about their choice for governor. Assume that survey respondents accurately report who they will...
  11. J

    Confidence Interval in Statistics test

    Hi all, I just had a test with the following question, of which I doubt the 'correct' answer: Taking a level of significance of 5% in a hypothesis test and not rejecting the null hypothesis, is the same as saying: A. We are 95% confident that the results have occurred by chance B. We are 95%...
  12. M

    Nonparametric data analysis

    I'm asking for advice. Topic of my research is brain iron accumulation. My task is the next . I have one dependent variable that is cathegorical and binominal(patient has the pathology or does not). And six independent variables that are continuous and nonpatametric. The question is :how can i...
  13. K

    Formula for the Confidence interval?

    Formula for the Confidence interval, assuming for a Sample whose standard deviation is same as Population. I need to know the exact formula. I need to know if there is any square root of n in the denominator. Anyone who knows the formula please share.
  14. A

    [AMOS] - interpretation of bootstrap indirect effects for one-tailed hypothesis

    Hello all, I'm testing for mediation using bootstrapping in AMOS. This method reports results for two-tailed significance, but my hypotheses are directional. With bootstrapping, significance is assessed based on confidence intervals - though a p-value is also provided. For regression, I would...
  15. A

    AMOS - interpretation of bootstrap indirect effects for one-tailed hypothesis

    Hello all, I'm testing for mediation using bootstrapping in AMOS. This method reports results for two-tailed significance, but my hypotheses are directional. With bootstrapping, significance is assessed based on confidence intervals - though a p-value is also provided. For regression, I would...
  16. D

    How do you create an acceptance criteria range for multiple populations?

    I am trying to create a quality control acceptance criteria range for my company's product. So here is an example of my problem: A car is traveling on a straight road and through scientific studies, I am able to predict the distance where the car will travel at a fixed time. From...
  17. Q

    P values from 95% CI using poisson distribution

    Hi, Hope I'm in the best place for an answer :) I have a study across 10 years. I have an incidence rate that was calculated for each year along with the 95% confidence interval using a Poisson distribution. My question is how do a get p-values for pairwise comparisons? I understand I can say...
  18. R

    Confusion between z and t values

    Hi, Alright so I have some confusion on when to use specific tests and the z vs t test. Given this example (not my homework) could someone please clarify. Alright say you have a random sample of size 200. You find the sample mean to be 10 and the sample standard deviation to be 5. What...
  19. J

    CI to percentage change in ICC

    I'm running fixed effects models to estimate changes in intra class correlations. I first run an unconditional model and then a second model including only level-2 factors. I'm interested in the reduction of the icc when adding only level-2 factors. I'm interested in expressing the...
  20. T

    Question about degrees of freedom in an independent sample t-test

    I've been asked the following question by a scientist who is not a statistician: Suppose we take a sample $x_1,…,x_n$ from a population that we can assume is normal (I don't think this assumption is critical). We then calculate the sample mean $\bar x¯$ and variance $s^2$. We then take a...