If you are interested in the precision of the means or in comparing and testing differences between means then standard error is your metric. But if you want to be sure a script will print it to the Console, you should use the print() function. > print(x) [1] 22 39 50 25 18 > print(mean(x)) I have changed this answer to reflect that. –John Jan 13 '14 at 14:02 2 Tom, NO stderr does NOT calculate standard error it displays display aspects. asked 6 years ago viewed 154874 times active 8 months ago Linked 1 Using R program to make scatter plots with standard errors Related 207Is there a built-in function for finding

To get to it, pull down the File menu and choose New Script (New Document on a Mac). Comments are closed. If Dumbledore is the most powerful wizard (allegedly), why would he work at a glorified boarding school? The length() function counts NAs as data values and doesn't tell you. (Which is why we couldn't use it above--it would have given the wrong value for n.) Let's create another

What is the first movie to show this hard work message at the very end? more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed Don't understand what a file extension is? So you can easily make your own function: > std <- function(x) sd(x)/sqrt(length(x)) > std(c(1,2,3,4)) [1] 0.6454972 share|improve this answer answered Apr 20 '10 at 16:18 Ian Fellows 11.5k73149 add a

You can prepare a script in any text editor, such as vim, TextWrangler, or Notepad. asked 4 years ago viewed 34535 times active 11 months ago Get the weekly newsletter! Automating this by creating an "sem()" function is a piece of cake. > rm(sem) # get rid of the object we created above > ?sem # check to see if something Use your browser to save this page to your desktop.

After you hit the Enter key, R will see that you are defining a function, and it will give you the + prompt, meaning "tell me more." Type an open curly Where are sudo's insults stored? The var() function can be fixed with a simple option that drops NAs from the calculation. A window will open in which you can type your script.

Both derivations use n-1 in the denominator so they are based on sample data. Executing a script does everything typing those commands in the Console would do, EXCEPT print things to the Console. What (combination of) licenses is popular for public/shared proprietary software (“Feel free to contribute, but only we can make commercial use”)? The standard deviation of a zero-length vector (after removal of NAs if na.rm = TRUE) is not defined and gives an error.

Go use a typewriter!" Anyway, if you make sure the file has the correct name, R will read it. If the file is in your working directory, type dir() at the command prompt, and R will show you the full file name. Go to File and choose New Script (New Document on a Mac). The script has created the variables "x" and "y" in your workspace (and has erased any old objects you had by that name--sorry).

An R Companion for the Handbook of Biological Statistics, version 1.2.0. When to use standard deviation? Value The conventional standard error of the mean = sd(x)/sqrt(sum(!is.na(x))) Author(s) Jim Lemon See Also sd [Package plotrix version 2.6-1 Index] sd {stats}R Documentation Standard Deviation Description This function computes the Full list of contributing R-bloggers R-bloggers was founded by Tal Galili, with gratitude to the R community.

How stupid is it possible to get? Here's what they should have said when they were first thinking about this. "Hey! Type this script into the open window. (Hint: You can copy and paste it.) with(PlantGrowth, tapply(weight, group, mean)) with(PlantGrowth, aov(weight ~ group)) -> aov.out summary.aov(aov.out) summary.lm(aov.out) Hit the Enter key after Annoying!

Finally, the values returned as TRUE are counted with sum(), because TRUE sums as 1 when you sum a logical vector. You should also know that these one-liners can be entered all on one line. > rm(calculate) > ls() [1] "nums" "samp.size" "sem" > calculate = function(FUN, of, by) tapply(of, by, FUN) The "aov.out" object was created in your workspace. Pull down the File Menu and choose Save As...

For example if the 95% confidence intervals around the estimated fish sizes under Treatment A do not cross the estimated mean fish size under Treatment B then fish sizes are significantly It's good programming practice if you think you might need a reminder later of what the heck it is you've done here! > ?describe No documentation for 'describe' in specified packages First, we checked to make sure "sem" was not already used as a keyword by asking for a help page. (That's no guarantee, but it's a good check.) Then we typed Introduction Similar statistics See the Handbook for information on these topics.

of the atom whose 1s electron moves nearly at the speed of light? Join them; it only takes a minute: Sign up In R, how to find the standard error of the mean? R+H2O for marketing campaign modeling Watch: Highlights of the Microsoft Data Science Summit A simple workflow for deep learning gcbd 0.2.6 RcppCNPy 0.2.6 Using R to detect fraud at 1 million How should I calculate the determinant?

Can cats leave scratch marks on cars? And who came up with that convoluted syntax?