standard error

  1. S

    How to compute the standard error with only sample size, mean of percentage and interquartile range?

    I have a percentage which is the rate of reduction. For example, each patient was measured on a scale several times, and the reduction rate was computed by (time 2-time 1)/time 1, I think. So, the reduction rate measures how much the performance is reduced in the second time. I have two...
  2. U

    Trouble understanding univariate logistic regression using categorical data

    Hello, I have a cancer dataset of 98 observations. Cancer detection rate was determined for 2 detection modalities (C and S). One of the independent variables of interest was a 3 tiered scoring system (possible scores: 3, 4, and 5). On univariate logistic regression, the score was...
  3. M

    Estimated standard error

    Why is it ok to estimate the population variance with the sample variance formula (i.e. the unbiased estimate of the variance). I understand how we can build a confidence interval using the central limit theorem and the following formula . But, the unbiased estimate of the variance means that...
  4. B

    Aggregate precision of a measurement instrument based on a sample of measurements whose true errors are known

    I want to estimate the accuracy and precision of aggregate data from an instrument that measures a variable that fluctuates over time by comparing a sample of its measurements to concurrent measurements made by a reference instrument. For this purpose, assume that the reference instrument...
  5. 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...
  6. C

    Understanding the use of the standard error of differences between two means (SEDM)

    Hello everyone, I am currently learning statistics using Van Emden's "Statistics for terrified biologists". I am trying to solve some exercices that the book offers you. One of the questions (1b) in the "Spare-time activities" section asks to find out if a mean value of 240 coming from the...
  7. R

    Calculate Standard Error over averaged responses or raw responses?

    Hi, I would like to calculate the standard error of my Dependent Variable. However, I have psycholinguistic data, which uses multiple ppts and multiple items. Thus, there are 2 ways of doing this: either by calculating SE over averaged responses (example 1) OR by calcualting SEs over raw...
  8. L

    Standard error calculation for more than one sample size

    Hi all I am conducting a meta analysis of pearsons r correlations. Whenever a study has presented more than one correlation I have averaged them into one correlation by converting them into fishers z scores. I now have the problem that I need to calculate a standard error and variance of the...
  9. L

    calculating standard error and variance of correlation estimates

    Hi all I understand that to calculate the standard error of correlation estimates converted into fishers z scores you need to follow - 1/(√N−3) Now I have the standard error , I am wondering how I calculate the variance please? Thanks
  10. hlsmith

    Bayesian Posterior: SD = SE?

    I was curious if the standard deviation in a Bayesian posterior is equal to the standard error?
  11. R

    Standard Error of Regression

    Im currently working on a dissertation. After running an OLS regression I have a statistic called the standard error of the regression. I have analysed the standard error of the coefficients but I do not know what the difference between the standard error of regression and coefficient are...
  12. kiton

    What can the standard errors tell me?

    Hello dear forum members! I wanted to share with you a couple graphs and seek your wisdom on the insights that I may be omitting. According to theory, there are merits to believe that relationship b/w X and Y is moderated by M. Notably, the relationship between X and M is likely to be...
  13. P

    Question on Standard Error

    If I need to compute the standard error for a bunch of students' test averages, and there are 20 students, each of whose score is itself an average of 8 tests, will my N for SEM=sdev/SqRt(N) be 20? Or will it be 160? In other words, if my bar graph plots the mean of 20 students' averages, but...
  14. I

    Multivariate models - standard error help

    I have 2 multivariate models created in R concerning nutrition Model 1 = -11.5±1.68 + 0.56±0.562 Intake + 16.6±0.165 Potassium concentration Model 2 = 16.6±0.123 Potassium concentration Both of these have come from the same data set. My question is, is it right that the standard error...
  15. S

    Regression analysis with sales forecasting

    Hello, I am in the process of using a regression model to help predict the forecast of soft drinks. I have 52 sets of weekly data and my independent variables are feature space, temperature, price, competitor price and competitor feature space after having omitted some predictor variables due...
  16. S

    Combining Standard Errors of 16 portfolios

    Hello everyone, I am working on Fama and French five factor model. I have run regression on 16 size- B/M excess portfolio returns on market premium, size premium, value premium, invesment premium and profitability premium. I have obtained coefficients of these factors, their standard errors...
  17. W

    Standard Error associated to a variable percentage

    Context: I am a programmer, not a statistician, and I have only some vague ideas of statistical concepts. Also, my english is far from perfect, be patient please. My client needs an estimate of the percentage of taxes he is going to pay, based on what happened in the recent past. He needs...
  18. E

    Estimating location of lower tail

    Say I have a sample, assumed from a Normal Distribution. I want to find a confidence interval for this parameter: L = \mu - \alpha * \sigma where \alpha is a known constant. I guess I should use the estimator: \bar{x} - \alpha*s But what standard error should I use? Just for...
  19. S

    Std. Error Multiple Regression Question

    Hi guys, I'm stuck at interpreting the stadard error. In single regression it's clear, it's just the average distance from the line. But I don't really understand what this looks like in multiple regression. Does the standart error depend on the estimate or do I have to look at it in an...
  20. S

    [FactorialANOVA] Which N to use when converting standard error to standard deviation?

    When converting standard error to standard deviation (using the formula SD = SE x SRT of N), I am having trouble with is which N to use - the N of the experimental group (for example), or the number of participants in the overall study. An ANOVA was conducted and I don't have the data but I...