Answer:
Step-by-step explanation:
Let x be the random variable representing the times a fire department takes to arrive at the scene of an emergency. Since the population mean and population standard deviation are known, we would apply the formula,
z = (x - µ)/σ
Where
x = sample mean
µ = population mean
σ = standard deviation
From the information given,
µ = 6 minutes
σ = 1 minute
the probability that fire department arrives at the scene in case of an emergency between 4 minutes and 8 minutes is expressed as
P(4 ≤ x ≤ 8)
For x = 4,
z = (4 - 6)/1 = - 2
Looking at the normal distribution table, the probability corresponding to the z score is 0.023
For x = 8
z = (8 - 6)/1 = 2
Looking at the normal distribution table, the probability corresponding to the z score is 0.98
Therefore,
P(4 ≤ x ≤ 8) = 0.98 - 0.23 = 0.75
The percent of emergencies that the fire department arrive at the scene in between 4 minutes and 8 minutes is
0.75 × 100 = 75%
<h3>
Answer: 3/5</h3>
Explanation:
P(B/A) is the shorthand way of saying "what is P(B) if we are 100% certain that event A has occured?"
Because events A and B are independent, they do not affect one another. The fact that A happens doesn't change P(B) at all.
Therefore, P(B) = P(B/A) when A & B are independent events.
Similarly, P(A) = P(A/B) when the two events are independent.
Answer:
1.56
Step-by-step explanation:
Given that :
Average height (μ) = 70 in
10% are taller than 72 in ; the standard deviation Given a normal distribution :
P(x > Z) = 0.10
Using a Z probability calculator, the Z value corresponding to P(x > Z) = 0.10 is 1.282
Z = 1.282
Using the Z relation:
Z = (x - μ) / σ
σ = standard deviation x = 72
1.282 = (72 - 70) / σ
1.282σ = 2
σ = 2 / 1.282
σ = 1.5600624
σ = 1.56
Answer is B I hope I’m right good luck
Answer:
2
Step-by-step explanation:
I think Mrs. Nygaard would need 2 hours to work over the weekend to finish grading the projects .
