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:
Step-by-step explanation:
+18
Answer: I think Value of x is 8 I’m not sure
Answer:
x = 
y²
Step-by-step explanation:
Any point (x, y ) on the parabola is equidistant from the focus and the directrix
Using the distance formula, then
= | x + 3 |
Squaring both sides
(x - 3)² + y² = (x + 3)² ← expanding both sides
x² - 6x + 9 + y² = x² + 6x + 9 ← subtract x² + 6x + 9 from both sides
- 12x + y² = 0 ( subtract y² from both sides )
- 12x = - y² ( divide both sides by - 12 )
x = y²
