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 ... $$\begin{array} { l | l | l | l }
10 \% \text { off } & 20 \% \text { off } & 30 \% \text { off } & 50 \% \text { off } \
\hline 0.35 & 0.75 & - 0.35 & 0.25
\end{array}$$
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 ... $$\begin{array} { l | l | l | l } 
10 \% \text { off } & 20 \% \text { off } & 30 \% \text { off } & 50 \% \text { off } \
\hline 0.35 & 0.75 & - 0.35 & 0.25
\end{array}$$
A)Legitimate
B)Not legitimate

Quizplus · Accepted Answer

The sum of probabilities exceeds 1 (0.35 + 0.75 + (-0.35) + 0.25 = 1.00, but negative probabilities are not possible), and probabilities cannot be negative, making this assignment not legitimate.

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