Let X= the number of households having at least one credit card: X∼Bin(n,p)
P(X=x)=(xn)px(1−p)n−x Given p=0.73,n=550
P(X=375)=(375550)0.73375(1−0.73)550−375
≈0.00159641506
P(X=376)=(376550)0.73376(1−0.73)550−376
≈0.00200888518
P(X=377)=(377550)0.73377(1−0.73)550−377
≈0.00250681398
P(X=378)=(378550)0.73378(1−0.73)550−378
≈0.0031019551
P(X=379)=(379550)0.73379(1−0.73)550−379
≈0.00380613195
P(X=380)=(380550)0.73380(1−0.73)550−380
≈0.00463079388
P(X=381)=(381550)0.73381(1−0.73)550−381
≈0.00558648314
P(X=382)=(382550)0.73382(1−0.73)550−382
≈0.00668222246
P(X=383)=(383550)0.73383(1−0.73)550−383
≈0.00792484056
P(X=384)=(384550)0.73384(1−0.73)550−384
≈0.00931826112
P(X=385)=(385550)0.73385(1−0.73)550−385
≈0.01086278867
P(375≤X≤385)≈0.0580255911
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