The probability that it rains at most 2 days is 0.00005995233 and the variance is 0.516
<h3>The probability that it rains at most 2 days</h3>
The given parameters are:
- Number of days, n = 7
- Probability that it rains, p = 95%
- Number of days it rains, x = 2 (at most)
The probability that it rains at most 2 days is represented as:
P(x ≤ 2) = P(0) + P(1) + P(2)
Each probability is calculated as:

So, we have:



So, we have:
P(x ≤ 2) =0.00000002097 + 0.00000168821 + 0.00005824315
P(x ≤ 2) = 0.00005995233
Hence, the probability that it rains at most 2 days is 0.00005995233
<h3>The mean</h3>
This is calculated as:
Mean = np
So, we have:
Mean = 7 * 92%
Evaluate
Mean = 6.44
Hence, the mean is 6.44
<h3>The standard deviation</h3>
This is calculated as:
σ = √np(1 - p)
So, we have:
σ = √7 * 92%(1 - 92%)
Evaluate
σ = 0.718
Hence, the standard deviation is 0.718
<h3>The variance</h3>
We have:
σ = 0.718
Square both sides
σ² = 0.718²
Evaluate
σ² = 0.516
This represents the variance
Hence, the variance is 0.516
Read more about normal distribution at:
brainly.com/question/4079902
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Answer:
about 15 hours
Step-by-step explanation:
You want to find t such that N(t)=200. Fill in the equation with that information and solve for t.
200 = 400/(1 +399e^(-0.4t))
1 +399e^(-0.4t) = 400/200 = 2 . . . . . multiply by (1+399e^(-0.4t))/200
399e^(-0.4t) = 1 . . . . . . . . . . . . . . . . . . subtract 1
e^(-0.4t) = 1/399 . . . . . . . . . . . . . . . . . .divide by 399
-0.4t = ln(1/399) . . . . . . . take the natural log
t = ln(399)/0.4 ≈ 14.972 . . . . . . . divide by -0.4, simplify
Rounded to tenths, it will take 15.0 hours for half the people to have heard the rumor.
8.4617....
Hope this helped you :)
Answer:
your answer to this is 68/25
Equation of a line is given by y - y1 = m(x - x1); where m is thw slope.
y - (-2) = 0(x - 0)
y = -2
For perpendicular lines, m2 = -1/m1
so, m2 = -1 / -1/3 = 3
Therefore the slope of a line perpendicular to the line is 3.