confidence interval

  1. R

    Funnel Plot - not based on rate, %, expected v actual count.

    Hi, I have been tasked with producing some funnel plots that are somewhat different to the ones i am used to producing. Normally i would be plotting something along the lines of: X-axis: Number of discharges Y-axis: rate of re-admissions. However, this time i have been asked to produce...
  2. F

    Sensitivity/Specificity: determining confidence intervals for a small sample size

    I'm conducting a study to determine the validity of a diagnostic test, by comparing its results to a reference standard. The variables I'm dealing with are all categorical. Sadly, I couldn't obtain a proper sample size since the prevalence of the disease is very low (about 6%). When I...
  3. B

    Having a problem with confidence intervals

    Here is the data, each line is for a different soccer franchise: Revenue/Value(Millions) 459/1835 563/323 369/1181 513/1000 406/990 304/822 276/800 285/656 340/646 276/413 175/384 186/372 196/333 206/329 205/308 161/274 187/262 145/261 143/258 142/198...
  4. B

    Help with ANOVA Analysis of Data

    I need to compute: The sum of squares associated with sex from the ANOVA table; Create histograms of the data used in the ANOVA for each level of Sex independently. Using this output and boxplot and apply do you think the assumptions of ANOVA have been met? How do I input the data of...
  5. rogojel

    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...
  6. C

    Constructing a Nonparametric confidence interval

    The following data consist of six TcCB measurements from a particular site: 0.26 1.84 0.78 1.59 0.84 1.53 Use the table below to construct the shortest possible non parametric confidence interval for x 0.25 (25th percentile) assuming that the confidence level must be at least 80%. So, I...
  7. R

    Confused with meta-analysis (Hedges); credibility intervals

    Dear All, Many thanks in advance for reading this - any help is gratefully received! I'm trying to combine the incidence rates for a complication of surgery (a ratio that i'm using as r). I am using the Hedges method Random Effects Model (as i have hetrogeneity in my studies). I want to...
  8. C

    95% confidence interval for the difference in true proportions for Chi-squared test

    Hello, Apologies if this has been covered, but if so I couldn't find it. Can anyone please tell me how to calculate the 95% confidence interval for the difference in true proportions for Chi-squared test (not for the Odds Ratio). I can work it out manually (I know it should be 0.082 to...
  9. C

    Estimating Confidence Intevals

    Hi, I have used a loglikelihood function to estimate 24 parameters. How do I construct a confidence interval given the Hessian (avaliated on the estimatives) and the gradiente(avaliated on the estimatives). Do I need both? What I saw is that, given that MLE is assymptoticaly normal I...
  10. F

    Local polynomial regression

    Hi, I have "smoothed" rather than using a linear line between X and Y. My R code is the following : # Loess model plot(Y ~ X) loess.model <- loess(Dataset$Y ~ Dataset$X) loess.model hat <- predict(loess.model) lines(Dataset$X[order(Dataset$X)], hat[order(Dataset$X)], col="red")...
  11. A

    confidence interval via bootstrapping

    Hello everyone, I'm new to Stata and trying to write code to find a confidence interval via bootstrapping for an odds ratio. For the odds in the numerator, the probability of event is calculated from averaging predicted probabilities after model coefficients are estimated using only...
  12. J

    Help with regression analysis and 95% confidence interval

    Hello! We have a couple of tasks for an assignment where we need to use regression analysis and 95% confidence interval, we're not sure on how to do it so figured I'd ask you guys for help. We don't really need the result of the actual task, but rather an detailed explanation to how to do...
  13. trinker

    Confidence intervals vs. Standard error bars

    I came across this article discussing the topic of confidence intervals and error bars ib plots and thought I'd share...
  14. G

    Error bars for unknown distribution

    I recently made a graph where I show the error bars for a certain number of "experiment". In another way, in my algorithm I'm minimizing the objective function so I would expect that increasing the sampling I'll get lower value of the objective function. As you can see in the graph, the...
  15. V

    Confidence Intervals affected by type of distribution

    How is the accuracy of confidence intervals affected by the population of interests distribution? I'm having some trouble wrapping my head around this. Thanks!
  16. M

    logistic regression predicted values and confidence interval

    Hello I have run a logistic regression with two independent variables. I have used transformed my y(sales) and my x1(population) and x2(water). I have my output in excel and i'm fine with the model. What I need help with is the equation for predicting values and for getting a range of...
  17. P

    Confidence intervals for difference between Poisson rates

    Hi, My data consists of occurrences of words in time windows. E.g.: Day; Word; Frequency 1; "dog"; 45 1; "cat"; 2 ... 2; "dog"; 90 2; "cat"; 4 ... I would like to estimate the ratio of day-to-day difference (i.e. for dog: 90-45/45 = 100%). For cat the increase is also 100%, but due to...
  18. S

    Reporting Beta + unstandardized CIs?

    Hello, I did a multiple regression analysis and for now always only reported the standardized effect sized (Beta). Since I heard that it would be good practice to also include the CIs, I wonder how this is done in practice - should I just present the standardized effect size next to the...
  19. A

    Sample Size Determination

    n=8, mean=5096, StDev=1460, SEmean=516.19 I need a 95% confidence interval no wider than $360. What is the minimum sample size required? I calculated this as 193, but was told I was incorrect. The issue may be with my bound, which I calculated to be 0.0706, or 7.06%. Using the formula...
  20. A

    CI for difference between means

    Control: n=13, Mean=32.77, StDev=32.77, SEMean=3.328 Treatment: n=16, Mean=42.01, StDev=17.2, SEMean=4.3 Point Estimate for treatment - control = 9.24 df = 27 What is the 98% CI? I calculated the ME as 13.45 and the CI as (-4.21, 22.69) Is this correct?