The research department of a board game company surveyed some shoppers at a local mall. The team asked shoppers how often they read the news, among other questions. Then the team played a memory card game with the shoppers. They recorded how many cards each shopper remembered.What is the probability that a randomly selected shopper reads the news 1-2 times a week given that the shopper remembered 1-3 cards?

解答

T h e rese a rc h d e p a r t m e n t o f a b o a r d g am e co m p an y s u r v eye d so m e s h o pp ers a t a l oc a l ma ll . T h e t e am a s k e d s h o pp ers h o w o f t e n t h ey re a d t h e n e w s, am o n g o t h er q u es t i o n s . T h e n t h e t e am pl a ye d a m e m ory c a r d g am e w i t h t h e s h o pp ers . T h ey recor d e d h o w man y c a r d s e a c h s h o pp er re m e mb ere d . Wha t i s t h e p ro babi l i t y t ha t a r an d o m l y se l ec t e d s h o pp er re a d s t h e n e w s 1 - 2 t im es a w ee k g i v e n t ha t t h e s h o pp er re m e mb ere d 1 - 3 c a r d s ?

\frac{1}{52}

十进制

0.01923 \dots

求解步骤

Find the probability of getting 1:

\frac{1}{52}

Since the events are independent, Use the formula

P (X_{1} \land X_{2} \land \dots \land X_{k}) = P (X_{1}) \cdot P (X_{2}) \cdot \dots \cdot P (X_{k})

= \frac{1}{52}