Investigators gave caffeine to fruit flies to see if it affected their rest The four treatments were a control a low caffeine dose of 1 mg ml of blood a medium dose 3 mg ml of blood and a higher caffeine dose of 5 mg ml of blood Twelve fruit flies were assigned at random to the four treatments three to each treatment and the minutes of rest measured over a 24 hour period were recorded The data follow Minutes of rest 413 422 453 330 Treatment Control Low dose Medium dose High dose Source Caffeine Error Total Assume the data are four independent SRSS one from each of the four populations of caffeine levels and that the distribution of the yields is Normal A partial ANOVA table produced by Minitab follows along with the means and standard deviation of the yields for the four groups One way ANOVA Rest Versus Caffeine DE 450 466 421 364 SS 11976 Level N Mean Control 3 427 00 Low Medium High MS 538 75 StDev 20 07 3 441 00 22 61 3 431 00 19 08 3 361 00 29 61 418 435 419 389 F P The numerator degrees of freedom for the ANOVA F test are A 11 B 2