Answer:
0.36427
Step-by-step explanation:
Mean = λ = 18 messages per hour
P(X = x) = (e^-λ)(λ⁻ˣ)/x!
P(X ≤ x) = Σ (e^-λ)(λ⁻ˣ)/x! (Summation From 0 to x)
But the probability required is that the messages thay come in an hour is between 15 and 20, that is, P(15 < X < 20)
P(15 < X < 20) = P(X < 20) - P(X ≤ 15)
These probabilities will be evaluated using a cumulative frequency calculator.
P(X < 20) = 0.65092
P(X ≤ 15) = poissoncdf(18, 15) = 0.28665
P(15 < X < 20) = P(X < 20) - P(X ≤ 15) = 0.65092 - 0.28665 = 0.36427.
You can use the Poisson distribution calculator here
https://stattrek.com/online-calculator/poisson.aspx
Answer:
4
5(2)+5(7)
Step-by-step explanation:
Part A= $27.32
Part B= $32.24
Answer:
15 children can divide them with eachother, each get 2 sweaters and 3 trousers
Step-by-step explanation:
15×2=30
15×3=45
Answer:
w = 3
l = 10
Step-by-step explanation:
l = 4w-2
P = 26cm
P = (l + w) × 2
26 = (4w-2+w) ×2
26 = (4w + w - 2) × 2
26 = ( 5w - 2 ) × 2
26 ÷ 2 = 5w -2
13 = 5w - 2
13 + 2 = 5w
15 = 5w
w = 3
l = 4w - 2
l = (4 × 3) -2
l = 12 - 2
l = 10
