Hello, I am a post grad student undertaking research on the ecology migratory freshwater shrimps in northern Australia. These shrimp undergo an mass migration from the estuary to the river at the end of the wet season and a goal of my research is to estimate the biomass of shrimp moving upstream. I have sampled the migration, to determine hourly migration rates, using fyke nets at periodic interval throughout the night over a period of 6 weeks. I couldn't sample every night and I couldn't leave nets out all night as there were significant crocodile risks. So I have half hourly migration rate data for four nights every week, for 6 weeks. I have completed multiple regression analysis to find the best model (using a range environmental predictor variables) to predict migration rate, and discharge came up as the strongest predictor. So I want to use the equation from the discharge and biomass regression to estimate migration biomass over the entire 6 week period. The end result will be an estimate of the total biomass moving upstream over 6 weeks. Because the total biomass estimate involves summing many predictions (of hourly biomass over each night) I am not sure how to calculate the confidence interval around the final prediction. Can I calculate the confidence interval for each prediction and then sum it to get the total confidence interval estimate? Is there an easy way to do this with a standard stats package such as Statisitica, SPSS or Excel? I would appreciate any feed back.
Thank you Peter
