However, if you write a formal lab report and you find the slope you MUST find the uncertainty in it. Menu Log in or Sign up Contact Us Help About Top Terms and Rules Privacy Policy © 2001-2016 Physics Forums Stat Trek Teach yourself statistics Skip to main content Home Tutorials That makes F the independent value and it should be plotted on the x-axis. Wähle deine Sprache aus.

Another way of understanding the degrees of freedom is to note that we are estimating two parameters from the regression – the slope and the intercept. If one were fitting a Bayesian model, then I could understand the use of MCMC methods. You systematically varied the force exerted on the spring (F) and measured the amount the spring stretched (s). Here is my data.

That should be ok, but what about the uncertainty? Du kannst diese Einstellung unten ändern. Estimation Requirements The approach described in this lesson is valid whenever the standard requirements for simple linear regression are met. For example, if your data points are (1,10), (2,9), (3,7), (4,6), a few bootstrap samples (where you sample with replacement) might be (2,9), (2,9), (3,7), (4,6) (i.e., the first data point

You would then get 100 different linear regression results (100 slopes and 100 intercepts). I get Monte Carlo, though it is decidedly brute force. We can model the linear regression as $Y_i \sim N(\mu_i, \sigma^2)$ independently over i, where $\mu_i = a t_i + b$ is the line of best fit. Therefore, why complicate estimates of standard errors?

What does かぎのあるヱ mean? d3t3rt, May 3, 2010 Sep 3, 2010 #19 Salish99 statdad said: ↑ In simple linear regression the standard deviation of the slope can be estimated as [tex] \sqrt{\frac{\frac 1 {n-2} \sum_{i=1}^n Thanks for the response! The Variability of the Slope Estimate To construct a confidence interval for the slope of the regression line, we need to know the standard error of the sampling distribution of the

Compute alpha (α): α = 1 - (confidence level / 100) = 1 - 99/100 = 0.01 Find the critical probability (p*): p* = 1 - α/2 = 1 - 0.01/2 mdmann00, Feb 15, 2010 Feb 15, 2010 #7 statdad Homework Helper In simple linear regression the standard deviation of the slope can be estimated as [tex] \sqrt{\frac{\frac 1 {n-2} \sum_{i=1}^n (y_i We focus on the equation for simple linear regression, which is: ŷ = b0 + b1x where b0 is a constant, b1 is the slope (also called the regression coefficient), x share|improve this answer edited Mar 29 '14 at 17:27 answered Mar 29 '14 at 0:53 queenbee 39027 add a comment| up vote 3 down vote There are a couple of rules

Because linear regression aims to minimize the total squared error in the vertical direction, it assumes that all of the error is in the y-variable. And if so, why should one not use that tool to do that calculation? The first true tells LINEST not to force the y-intercept to be zero and the second true tells LINEST to return additional regression stats besides just the slope and y-intercept. Therefore, s is the dependent variable and should be plotted on the y-axis.

However, a computer calculates this estimate with an iterative computer algorithm like the Newton-Raphson or golden search algorithm. 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 David C. With respect to computer estimation of b0 and b1, statistics programs usually calculate these through an iterative computer algorithm.

you have a vector of $t$'s $(t_1,t_2,...,t_n)^{\top}$ as inputs, and corresponding scalar observations $(y_1,...,y_n)^{\top}$. I do a linear regression and get an equation for a line of best fit, say y = 0.3x + 0.1 or something. item at the bottom of the Tools menu, select the Add-Ins... Sum of neighbours Security Patch SUPEE-8788 - Possible Problems?

Select a confidence level. With error bars, this is what it should look like: Now, I want to fit a linear function to this data. d3t3rt, May 2, 2010 May 2, 2010 #15 mdmann00 Aloha d3t3rt, If closed forms of the standard errors in linear regression exist, are these not what are used to estimated the Even with this precaution, we still need some way of estimating the likely error (or uncertainty) in the slope and intercept, and the corresponding uncertainty associated with any concentrations determined using

Any clarifying points you can provide would be much appreciated. Also, inferences for the slope and intercept of a simple linear regression are robust to violations of normality. That is, we are 99% confident that the true slope of the regression line is in the range defined by 0.55 + 0.63. As a statistician, I despise the use of Excel for any statistical analysis!

Comments are closed. regression standard-error share|improve this question edited Apr 14 '14 at 7:05 asked Mar 28 '14 at 20:11 user3451767 11319 marked as duplicate by gung, Nick Stauner, Momo, COOLSerdash, Glen_b♦ Mar 29 How can I get the key to my professors lab? Wird geladen...

Method 1 - use uncertainty of data points I could get the ratio of C/d by just looking at each data point. Anmelden Transkript Statistik 15.826 Aufrufe 46 Dieses Video gefällt dir? But that's the meaning of standard error of the slope; when taking data, you might just as well have measured (3,7) instead of (2,9). Hinzufügen Playlists werden geladen...

Check the Analysis TookPak item in the dialog box, then click OK to add this to your installed application. I thought to myself: well, maybe it has to do with using the uncertainty in x and the uncertainty in y. The dependent variable Y has a linear relationship to the independent variable X. Select seams easy and fast way?

As an exercise, I leave you to perform the minimisation to derive $\widehat{\sigma}^2 = ||Y - X\widehat{\beta}||^2$. Unless the histogram of residuals evidences a strong departure from Normality, I would not be concerned with non-Normal errors. statdad, May 3, 2010 May 3, 2010 #18 d3t3rt Statdad, thank you for fixing my statement about known standard errors and distributional forms for the sample slope and intercept. Melde dich an, um dieses Video zur Playlist "Später ansehen" hinzuzufügen.

mdmann00, May 2, 2010 May 2, 2010 #16 d3t3rt Here is a website outlining many of Excel's shortcomings: http://www.cs.uiowa.edu/~jcryer/JSMTalk2001.pdf I am very suspect of the algorithms that Excel uses to calculate How to Find the Confidence Interval for the Slope of a Regression Line Previously, we described how to construct confidence intervals.