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Piyumi
Calcite | Level 5

I need to find the effect of treatments on mortality rate of insects. My dependent variable is mortality rate and my independent variable is treatments. Each treatment was replicated 4 times. The exposure times of the treatments are different, but, within a treatment, the exposure times are the same. When I conducted one-way ANOVA without considering the time effect, I see treatments have a significant effect on the survival. However, the exposure time also affect the dependent variable mortality. I tried separating the effect of time using multiple logistic regression and ANOVA. However, I think the program identifies time and treatment both as a single variable. Please see the attached data sheet. Any advise on this would be much appreciated.

Death rateTreatmentTime (days)
0.3R28
0.1R28
0.1R28
0.4R28
0.7R416
0.7R416
0.7R416
0.7R416
0.9R624
0.8R624
0.8R624
0.9R624
1 REPLY 1
PGStats
Opal | Level 21

Treatment and time are perfectly confounded in your experimental design. There is no way you can tell them apart. - PG

PG

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