Paleolithic body paint and perhaps in ritual. Undisputed evidence of art only becomes common in the Upper Paleolithic. Lower Paleolithic Acheulean tool users, according to Robert G. Bednarik, began to engage in symbolic behavior such as art around 850,000 BP. They decorated themselves with beads and collected exotic stones for aesthetic, rather than utilitarian qualities. According to him, traces of the pigment ochre from late Lower Paleolithic Acheulean archaeological sites suggests that Acheulean societies, like later Upper Paleolithic societies, collected and used ochre to create rock art. Nevertheless, it is also possible that the ochre traces found at Lower Paleolithic sites
Mean and predicted response decrease, but the variance of the mean of the formula_19 does shrink with increased sampling, because the variance in formula_21 and formula_22 decrease, so the mean response (predicted response value) becomes closer to formula_23. This is analogous to the difference between the variance of a population and the variance of the sample mean of a population: the variance of a population is a parameter and does not change, but the variance of the sample mean decreases with increased samples. The general linear model can be written as Therefore, since formula_25 the general expression for the variance of the mean response