Answer:
The correct answer is option 'a' : 120 is more than 2.5 standard deviations above the expected value.
Step-by-step explanation:
For an exponential distribution we have
The expected value μ = 80
No of trails n = 200
Thus we have
The deviation is related to expected value and probability as
Thus the values between the given deviation is
Now since 120 successes are out of the range of [62.75,97.25] thus 120 is more than the expected value.
Check the picture below.
based on the equation, if we set y = 0, we'd end up with 0 = 0.5(x-3)(x-k).
and that will give us two x-intercepts, at x = 3 and x = k.
since the triangle is made by the x-intercepts and y-intercepts, then the parabola most likely has another x-intercept on the negative side of the x-axis, as you see in the picture, so chances are "k" is a negative value.
now, notice the picture, those intercepts make a triangle with a base = 3 + k, and height = y, where "y" is on the negative side.
let's find the y-intercept by setting x = 0 now,
now, we can plug those values on A = (1/2)bh,
