Answer:
The answer is
Step-by-step explanation:
If we assume that people cannot taste a difference between bottled water, then the probability of identifying tap water is 0.5
Thus, P(identify tap water)=0.5
The probability that at least 8 of the 9 people identify the tap water correctly is the sum of the probabilities
- 8 of 9 people identified correctly or
- 9 of 9 people identified correctly
Since P(identify tap water)=0.5 each probabilities are the same and equal to
=
So we have =