Given: The probability of an event must lie between \( 0 \) and \( 1 \), inclusive.
Step 1: Understanding Probability Range
- Probability of any event \( P(E) \) satisfies: \[ 0 \leq P(E) \leq 1 \]
Step 2: Checking the Given Options
- \( 0 \) is a valid probability (impossible event). - \( \frac{4}{5} = 0.8 \), which is within the valid range. - \( \frac{5}{4} = 1.25 \), which is greater than \( 1 \), so it is not a valid probability. - \( 1 \) is a valid probability (certain event).
Final Answer: \(\frac{5}{4}\)
Based upon the results of regular medical check-ups in a hospital, it was found that out of 1000 people, 700 were very healthy, 200 maintained average health and 100 had a poor health record.
Let \( A_1 \): People with good health,
\( A_2 \): People with average health,
and \( A_3 \): People with poor health.
During a pandemic, the data expressed that the chances of people contracting the disease from category \( A_1, A_2 \) and \( A_3 \) are 25%, 35% and 50%, respectively.
Based upon the above information, answer the following questions:
(i) A person was tested randomly. What is the probability that he/she has contracted the disease?}
(ii) Given that the person has not contracted the disease, what is the probability that the person is from category \( A_2 \)?