# p-value

1. ### How do I test the significance of my correlation coefficients for various regressions

Hi, I have a set of 25 points and I used a TI-84 calculator to calculate the linear, quadratic, logistic, exponential, and power regression models for this data set. I have, likewise, obtained the r^2 value for each of these regressions. Some of these r^2 values appear to be quite similar. For...
2. ### Is it meaningful to calculate a p-value based on a convenience sample?

Ignore the bootstrap as a possibility. If the answer is no, then what is the point of stating the p-value (especially if it is, say, 0.10)?
3. ### Pleease help!? Filling in "blanks" in Regression Output

Hello! Can someone please explain, I need to fill in the blanks marked They provide this info in a row: Coeff:-9074.674 Std.Err: ?? p-value: 0.000 95% Conf.Intervall: -13272.86, -4876,485 How do I calculate Std.Err & t-stat here? Please help me, thank you! :) Best Regards
4. ### Conceptual queries in modeling

Hi all, I am from engineering background. I would require your help in certain conceptual questions in modeling. Your help would be greatly appreciated! Following are my few questions... (Pointers on these questions would help me , else you may direct me to any useful resources.) 1)If a...
5. ### Samples p-value in ANOVA

Hi, my problem regards ANOVA: if the ANOVA test is sginificant (p-value<0.05), is there a way to calculate a p-value for each sample, in order to detect which is (are) significant different from the others? I know there are some post hoc tests, like Tukey or Scheffé, but they all compare...
6. ### Finding Significant Difference between Linear Regressions

Hello. I have a scatterplot with two different sets of data plotted. Each individual set has its own linear regression formula and R-squared value. What type of test could I run on Microsoft Excel to get a p value to see if one dataset's trend is significantly different than that of the other...
7. ### Comparing two estimated distributions

I estimated the density function (adaptive kde) from two samples (one of small size) and the cdf using approxfun() and integrate() in R. Now, I would implement a ks test to know if the two distributions are similar. I guess I have two options: Either, I draw two samples and use the function...
8. ### p value of the constant, can I ignore it?

I'm analysing the influence of various factors on hare harvests in a specific are. E.g. How do the hare harvests change when the fox harvests increase. Term Coef | SE-Coef | T-Value | P-Value Constant | 415.0 | 28.7 | 14.46 | 0.000 Annual fox harvest | -1.054 | 0.193 | -5.45 | 0.001...
9. ### How can I get R to generate p-value when doing a correlation matrix?

How can I get R to generate p-value for each correlation when doing a correlation matrix? Here are my current steps: > M <- cor(data1) # get correlations into Matrix > library('corrplot') # import corrplot library > corrplot(M, method = "circle")...
10. ### 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...
11. ### 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...
12. ### Significant p-value, but 95%CI includes 0

Hello everyone, I have the following problem: The result of a Pearson correlation (sample size = 177) was significant, r = .127, p = .048 (one-tailed). However, the 95% confidence interval includes zero, 95% CI [-.02, .27]. How is it possible to have a significant p, when the CI...
13. ### Mixing lasso with OLS

Hi, I am looking at a data set of 45 continuous IV and 1 DV, trying to find an acceptable regression model. I tried the lasso with cross-validation and ended up with about 10 non-zero coefficients in the best model. However, when I ran the sanity test of building the OLS model with the 10...
14. ### how to measure p-value if dependent and independent come from different questionnaire

I have in 1 dataset data from 1 questionnaire for students (which leads to the dependent: autonomy-score) and 1 questionnaire for teachers (which leads to the independent: autonomy-support-score). The independent is dichotomized in negative scores and positive scores. Can anyone help me...
15. ### Confidence intervals vs. p -value

Hi, we just had a very interesting discussion about the role of confidence intervals and p values in determining significance and I realised there is a point that is quite unclear to me, so, here is the question: I am considering a simple situation, a two sample proportion test, say. For each...
16. ### Significant difference between frequency of words in a text

Hi, I guess it is a very basic question. Imagine two text samples, e.g. one text on someone's mother and the other on father. Text about mother includes word love for 80 times (1% of all words) and bout father for 50 times (0.8% of all words). Can we establish if this difference is significant...
17. ### Need help with medical study

Hi, I'm writing a medical paper on asthma and I'm afraid I 've reached a point where I am unconfident of my statistics knowledge. I am hypothesizing that there is a relationship between elevated concentrations of a substance in the blood (we will call it X) and severity of asthma...
18. ### Can a relative risk and odds ratio differ in p-value?

With increasing incidence of the outcome, odds ratios tend to overestimate relative risks. I was wondering whether they also start to differ in p-values. So my question is: could there be a situation where the (unadjusted) odds-ratio reaches statistical significance, but the (unadjusted)...
19. ### How to calculate p-value of two-sample t-test

I have 2 independent data sets, and I know the following about each of them: mean, SD, and sample size. I calculated the t-statistic just fine my.t.test<-function(mu1, mu2, sd1, sd2, n1,n2){ t=(mu1-mu2)/sqrt((sd1)^2/n1+(sd2)^2/n2) return(t) } I know that the degrees of freedom...
20. ### 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