# standard error

1. ### Optimization of variables with significantly different standard errors.

Hi everyone! I have some issues related to the title at hand, and hopefully you guys can help. Sorry for the long post. I have forecasted mean variance data given to me for about 10 different variables. I need to optimize those variables. I have historical data for those 10 different...
2. ### SEM in AMOS, residual errors

Hello everybody, I need to report on a paper a model tested through SEM analyses in AMOS graphic, In the figure referees asked me to report "circles representing residual error measures for each indicator items"... well, I think I'll find the values in 'estimates'-->'variances', but which...
3. ### Does the standard error of the regression not need to be corrected by n?

The standard error of an estimator is defined as the square root of the the estimator variance (or mean squared error (MSE) for unbiased estimators). More specifically, if we wanted to get the standard error of the sample mean \bar{X}, we would divide the variance of the sample that \bar{X} was...
4. ### Linear Regression help :D

Hey guys i was having trouble doing my econometrics homework so i'm going to see if anyone here can help me do this question :D So we have to assume that the data we are given can be described by the simple linear regression model: yi=B1+b2xi + ei where B1 and B2 are beta signs and ei...
5. ### comparing regression coefficients between different models to see if they are similar

Hi all; This is a very elementary problem; but unfortunately, my strengths do not like in statistics: I am trying to describe plant growth over time using accumulated temperature (dd) as my independent variable and the plants 'growth stage' (gs) as my dependent variable. The shape of the...

7. ### generating dummy from piece of string

Hey guys. I'm new to Stata and would really appreciate anyone who can help me. My data is currently in excel and many of the data points contain a numerical value followed by "(s)" indicating the standard error is greater than 40% of that value. My ultimate goal is to get this data into...
8. ### Standard error calculation fails

Hello all. I would really appreciate any help in solving this problem: There is an interesting article on funnel plots on the web: http://www.kurtosis.co.uk/technique/funnel/ and it works reallly well if the event rate is less than 1. However, we have a dataset in which the event rate is...
9. ### Newbie question on central limit theorem and standard error

Hi all: First post here, hopefully in the right forum. I'm trying to teach myself basic stats (using the book Statistics in a Nutshell) and I'm trying to get my head round something. The book gives a brief discussion of the Central Limit Theorem, and then says that it shows...
10. ### detection rate question

Hi, I have sort of a backwards question. I have a calculated detection rate and its standard error, and I know the number of positives that were detected. I am trying to calculate the total number of positives (detected and non-detected), and a 95% confidence interval for that estimate. The...
11. ### Standard Deviation not Equal to Standard Error

Question: If the standard deviation of a particular sample with size N is not equal to the standard error for samples of the same size. Can you tell which is larger? If so, why? Choices: A. Yes. The standard deviation gets smaller with increasing sample size, so it must be smaller...
12. ### Standard Error - interpretation and relative standard error

Hi, I am unclear about how to interpret the Standard Error of the Mean (SEM) directly. For example, when a mean is reported as 5.00 + 0.50SEM, how do you directly relate the 0.50 to 5.00? To help address this question I have written dot points about what I know about the SEM and interspersed...
13. ### Determining the Standard Deviation (vice Standard Error) of regression coefficients?

This is a question I’ve been wondering about for a while, but perhaps it’s not possible or perhaps I just need a point in the right direction. I constructed the attached mock data samples with four variables, A, B, C, D, each of which is either present (1) or not (0). The true value for each...
14. ### By which dimension to cluster standard errors in linear regression?

Hello, This is my first post to this forum. All direct help, as well as references to other sources discussing the subject, are greatly appreciated. I am not sure by which variable/dimension to do clustering for standard errors in a specific linear regression model. I have firm-level...
15. ### Adding up the coefficients of a contemporaneous and a once-lagged variable

Hello, I'm stuck on what's probably a trivial problem, but I can't figure out how to go about it as I am a semi-beginner, so I would really appreciate the help of anyone who can assist me. I'm doing empirical work and I want to combine the effects of a variable and a once-lag of the variable...
16. ### Cluster Sampling and Standard Errors

I looked around to find the answer on this site but did not find any, so I apologize if this has been discusses recently and would welcome redirection. My question deal with descriptive and inferential statistics and Cluster Samples. I was given 6 data sets which I got statistics for but my...
17. ### Confidence interval from st. error when the mean must be positive

Hello all, (Statistical newbie here - learning some basic concepts) Some background (you can probably skip to the 'important bit', but just in case...): I am calculating the mean number of stratospheric sudden warmings (SSWs) per year. An SSW is a winter atmospheric event which happens...
18. ### how to calculate adjusted standard error to report with adjusted means for ancova

How to calculate adjusted mean and adjusted std error? I'm using regression as ancova in R as below. Condition is coded: 0 = control, and 1 = experimental. I understand that the intercept is the adjusted mean for the control and the intercept + condition coefficient is the adjusted...
19. ### How to calculate adjusted mean and adjusted std error using lm()

I'm using regression as ancova as below. Condition is coded: 0 = control, and 1 = experimental. I understand that the intercept is the adjusted mean for the control and the intercept + raw condition coefficient is the adjusted mean for the experimental group. My question is, can i...
20. ### Writing a mean loop.. (literally)

So my test data looks like this: structure(list(day = c(1L, 1L, 2L, 2L, 2L, 3L, 3L, 4L, 4L, 4L ), Left = c(0.25, 0.33, 0, 0, 0.25, 0.33, 0.5, 0.33, 0.5, 0), Left1 = c(NA, NA, 0, 0.5, 0.25, 0.33, 0.1, 0.33, 0.5, 0), Middle = c(0, 0, 0.3, 0, 0.25, 0, 0.3, 0.33, 0, 0), Right = c(0.25...