回答: #P _((x = 4ヘッド))= 0.15625# 説明: #p = 0.5# #q = 0.5# #P _((x = 4ヘッド))= "^ nC_xp ^ xp ^(n-x)# #P _((x = 4ヘッド))= "^ 5C_4(0.5)^ 4(0.5)^(5-4)# #P _((x = 4ヘッド))= = 5(0.5)^ 4(0.5)^ 1# #P _((x = 4ヘッド))= = 5(0.0625)(0.5)# #P _((x = 4ヘッド))= 0.15625#