2 to the first is 2 because there is only one 2
The difference between the 2 times would be .055 seconds...
Let X be a discrete random variable with geometric distribution.
Let x be the number of tests and p the probability of success in each trial, then the probability distribution is:
P (X = x) = p * (1-p) ^ (x-1). With x = (1, 2, 3 ... n).
This function measures the probability P of obtaining the first success at the x attempt.
We need to know the probability of obtaining the first success at the third trial.
Where a success is defined as a customer buying online.
The probability of success in each trial is p = 0.3.
So:
P (X = 3) = 0.3 * (1-0.3) ^ (3-1)
P (X = 3) = 0.147
The probability of obtaining the first success at the third trial is 14.7%
Set up a proportion
EA / EB = ED/ EC
16 / (5x + 2 + 16) = 12 / (12 + 24)
16/(5x + 18) = 12 / 36 Cross multiply
16 * 36 = (4x + 18)*12 Remove the brackets
576 = 48x + 216 Subtract 216 from both sides.
360 = 48x Divide by 48
360/48 = x
7.5 = x
