A group of eight unrelated patients with retinitis pigmentosa(RP) were identified with a distinct point mutation in the genecoding for rhodopsin. The mutation corresponds to a singleamino acid substitution in rhodopsin protein. Their ocularfindings were compared with 140 unrelated RP patients without thismutation. The results are presented below for visual fieldarea. Assume that the population distribution of visual fieldis normal and the variances of the two populations areequal.
a) Conduct a two-sided test at the0.05 level of significance to determine whether there is adifference visual field area between those with and without themutation. Report a p-value.
b) What are the assumptions for thistest?