Confidence intervals in lmer
U could try the predict function with se.fit=true. I believe this should give u the predicted score and se and u can calculate CI from there. U'll have to create an input matrix with the score u want to predict for. Chris Howden Founding Partner Tricky Solutions Tricky Solutions 4 Tricky Problems Evidence Based Strategic Development, IP Commercialisation and Innovation, Data Analysis, Modelling and Training (mobile) 0410 689 945 (fax / office) chris at trickysolutions.com.au Disclaimer: The information in this email and any attachments to it are confidential and may contain legally privileged information. If you are not the named or intended recipient, please delete this communication and contact us immediately. Please note you are not authorised to copy, use or disclose this communication or any attachments without our consent. Although this email has been checked by anti-virus software, there is a risk that email messages may be corrupted or infected by viruses or other interferences. No responsibility is accepted for such interference. Unless expressly stated, the views of the writer are not those of the company. Tricky Solutions always does our best to provide accurate forecasts and analyses based on the data supplied, however it is possible that some important predictors were not included in the data sent to us. Information provided by us should not be solely relied upon when making decisions and clients should use their own judgement.
On 27/09/2011, at 23:23, Adam Hayward <a.hayward at sheffield.ac.uk> wrote:
Dear list members, I have a significant interaction between two continuous variables (it happens to be a mixed model in lmer, but I imagine the same is applicable to a glm). The interaction tells me that the relationship between z and y changes as a function of x, but I want to know whether y has a significant effect on z at a given value of x. For instance, the interaction might show that the relationship between body weight and fitness changes with age, but I want to know if the association between body weight and fitness is significantly positive at the age of 1. Therefore, I'd like to estimate 95% CIs or SEs around the association between body weight and fitness at a given age, but have yet to work out how to do it. Any suggestions would be greatly appreciated. Best wishes, Adam -- Adam Hayward Post-Doctoral Research Associate Department of Animal and Plant Sciences Alfred Denny Building University of Sheffield Western Bank Sheffield S10 2TN UK [[alternative HTML version deleted]]
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