In: Statistics and Probability
A particular lake is known to be one of the best places to catch a certain type of fish. In this table, x = number of fish caught in a 6-hour period. The percentage data are the percentages of fishermen who caught x fish in a 6-hour period while fishing from shore.
| x | 0 | 1 | 2 | 3 | 4 or more | 
|---|---|---|---|---|---|
| % | 43% | 35% | 15% | 6% | 1% | 
(b) Find the probability that a fisherman selected at random
fishing from shore catches one or more fish in a 6-hour period.
(Enter a number. Round your answer to two decimal places.)
(c)Find the probability that a fisherman selected at random
fishing from shore catches two or more fish in a 6-hour period.
(Enter a number. Round your answer to two decimal places.)
(d) Compute μ, the expected value of the number of fish caught
per fisherman in a 6-hour period (round 4 or more to 4). (Enter a
number. Round your answer to two decimal places.)
μ =  fish
(e) Compute σ, the standard deviation of the number of fish
caught per fisherman in a 6-hour period (round 4 or more to 4).
(Enter a number. Round your answer to three decimal places.)
σ =  fish
SOLUTION:
From given data,
(a) Convert the percentages to probabilities and make a histogram of the probability distribution.

(b) Find the probability that a fisherman selected at random fishing from shore catches one or more fish in a 6-hour period.
the probability that a fisherman selected at random fishing from shore catches one or more fish in a 6-hour period.
= 0.35+0.15+0.06+0.01 =0.57
(c) Find the probability that a fisherman selected at random fishing from shore catches two or more fish in a 6-hour period.
the probability that a fisherman selected at random fishing from shore catches two or more fish in a 6-hour period.
= 0.15+0.06+0.01 =0.22
(d) Compute μ, the expected value of the number of fish caught per fisherman in a 6-hour period (round 4 or more to 4). (Enter a number. Round your answer to two decimal places.) μ = fish
We simplify the value of
x=4 or more as x=4
Hence,
| X | Probability (p) | P*X | X2 | P*X2 | 
| 0 | 0.43 | 0 | 0 | 0 | 
| 1 | 0.35 | 0.35 | 1 | 0.35 | 
| 2 | 0.15 | 0.3 | 4 | 0.6 | 
| 3 | 0.06 | 0.18 | 9 | 0.54 | 
| 4 | 0.01 | 0.04 | 16 | 0.16 | 
| Total | 1 | 0.87 | 1.65 | 
Expected value =

(e) Compute σ, the standard deviation of the number of fish caught per fisherman in a 6-hour period (round 4 or more to 4). (Enter a number. Round your answer to three decimal places.) σ = fish
Standard deviation =
= 

