Question

1. 60% of a department stores customers have a credit card from that department store, and 30% of a store’s customers make at least 1 purchase per month on average. Finally, 80% of the customers who make at least 1 purchase per month have a store’s credit card. Of the customers who do not make at least 1 purchase per month, what is the probability a randomly chosen customer has a store’s credit card? (please round your answer to 4 decimal places)

2. The time between customers entering a store is exponentially distributed with a mean of 14 minutes. If one customer just entered the store what is the probability that it will be at least 16 minutes before another customer enters the store?

Answer 1

1)

Answer)

Lets say we have a sample size of 100.

60% of a department stores customers have a credit card from that department store = 60% of 100 = 60.

30% of a store’s customers make at least 1 purchase per month on average = 30.

80% of the customers who make at least 1 purchase per month have a store’s credit card = 80% of 30 = 24.

Probability = favorable/total

Total = who do not purchase at least 1 = 100 - 30 = 70

Favorable = have credit card = 60 - 24 = 36.

Probability = 36/70 = 0.51428571428 = 0.5143