Question

John runs a computer software store. Yesterday he counted 139 people who walked by the store, 62 of whom came into the store. Of the 62, only 22 bought something in the store.

(a) Estimate the probability that a person who walks by the store will enter the store. (Round your answer to two decimal places.)


(b) Estimate the probability that a person who walks into the store will buy something. (Round your answer to two decimal places.)


(c) Estimate the probability that a person who walks by the store will come in and buy something. (Round your answer to two decimal places.)


(d) Estimate the probability that a person who comes into the store will buy nothing. (Round your answer to two decimal places.)

Answer 1

Number of people who walked by the store = 139

Number of people who came into the store = 62

Number of people who bought something = 22

(a) Estimate the probability that a person who walks by the store will enter the store.  

P[ person who walks by the store will enter the store ] = Number of people who came into the store / Number of people who walked by the store

P[ person who walks by the store will enter the store ] = 62 / 139

P[ person who walks by the store will enter the store ] = 0.45

(b) Estimate the probability that a person who walks into the store will buy something.

P[ person who walks into the store will buy something ] = Number of people who bought something / Number of people who came into the store

P[ person who walks into the store will buy something ] = 22/62

P[ person who walks into the store will buy something ] = 0.35

(c) Estimate the probability that a person who walks by the store will come in and buy something.

P[ who walks by the store will come in and buy something ] = Number of people who bought something /Number of people who walked by the store

P[ who walks by the store will come in and buy something ] = 22/139

P[ who walks by the store will come in and buy something ] = 0.16

(d) Estimate the probability that a person who comes into the store will buy nothing.

P[ person who walks into the store will buy nothing ] =1 - P[ person who walks into the store will buy something ]

P[ person who walks into the store will buy nothing ] = 1 - 0.35

P[ person who walks into the store will buy something ] = 0.65