Many stores run "secret sales": Shoppers receive cards that determine how large a discount they get,but the percentage is revealed by scratching off that black stuff only after the purchase has been totaled at the cash register.The store is required to reveal (in the fine print)the distribution of discounts available.Determine whether the following probability assignment is legitimate. Probability of ... $$\begin{array} { l | l | l | l }
10 \% \text { off } & 20 \% \text { off } & 30 \% \text { off } & 50 \% \text { off } \
\hline 0.05 & 0.30 & 0.45 & 0.10
\end{array}$$
A)Legitimate
B)Not legitimate

Question

Many stores run "secret sales": Shoppers receive cards that determine how large a discount they get,but the percentage is revealed by scratching off that black stuff only after the purchase has been totaled at the cash register.The store is required to reveal (in the fine print)the distribution of discounts available.Determine whether the following probability assignment is legitimate. Probability of ... $$\begin{array} { l | l | l | l } 
10 \% \text { off } & 20 \% \text { off } & 30 \% \text { off } & 50 \% \text { off } \
\hline 0.05 & 0.30 & 0.45 & 0.10
\end{array}$$
A)Legitimate
B)Not legitimate

Quizplus · Accepted Answer

The probability assignment is not legitimate because it does not add up to 1. The given probabilities are 0.06, 0.15, 0.29, 0.35, and 0.05, which add up to 0.90. This means that there is a missing probability of 0.10 that has not been accounted for. In order for a probability assignment to be legitimate, the probabilities must add up to 1.

Many Stores Run "Secret Sales": Shoppers Receive Cards That Determine