Final answer:
The probability of rolling exactly 4 out of 5 six-sided dice and getting a "1" on each is found using the binomial probability formula and is approximately 0.0032.
Step-by-step explanation:
To calculate the probability that exactly 4 of the 5 dice land showing a "1", we can use the binomial probability formula. The binomial probability formula is given by:
P(X = k) = (n choose k) · (p)^k · (1-p)^(n-k)
where:
- n is the number of trials (in this case, 5)
- k is the number of successes we want (in this case, 4)
- p is the probability of success on a single trial (for a die, the probability of rolling a "1" is 1/6)
- (1-p) is the probability of failure on a single trial (the probability of not rolling a "1")
Using this formula, we can calculate:
P(X = 4) = (5 choose 4) · (1/6)^4 · (5/6)
Here, (5 choose 4) represents the number of ways we can choose which 4 of the 5 dice will show a "1", which is 5. Thus, the calculation becomes:
P(X = 4) = 5 · (1/6)^4 · (5/6) = 5 · (1/1296) · (5/6) = (5 · 5) / (1296 · 6)
P(X = 4) = 25 / 7776 = 0.003215 (approximately, rounded to six decimal places)
Therefore, the probability of rolling exactly 4 out of 5 dice showing a "1" is approximately 0.0032.