A study of color vision in squirrels used an apparatus conta

A study of color vision in squirrels used an apparatus containing three small translucent panels that could be separately illuminated. The animals were trained to choose. by pressing a lever, the panel that appeared different from the other two. (During these \"training\" trials, the panels differed in brightness, rather than color.) Then the animals were tested for their ability to discriminate between various colors. In one series of \"testing\" trials on a single animal, one of the panels was red and the other two were white; the location of the red panel was varied randomly from trial to trial. In 75 trials, the animal chose correctly 45 times and incorrectly 30 times.31 How strongly does this support the interpretation that the animal can discriminate between the two colors? Test the null hypothesis that the animal cannot discriminate red from white. Use a directional alternative and let alpha = 0.02. Why is a directional alternative appropriate in this case?

Solution

Test of p = 0.5 vs p < 0.5

98% Upper
Sample X N Sample p Bound Z-Value P-Value
1 30 75 0.400000 0.516178 -1.73 0.042

Using the normal approximation.

sp as p>0.02

so we accept H0

b) we gel less number of sample in incorrect ditectation so we use left tail test