This one is a bit more complicated but i believe the answer is -1/4
Answer:
I don't know if I understand
Answer:

And using the cumulative distribution function we got:

The probability that preparation is within 2 minutes of the mean time is 0.134
Step-by-step explanation:
For this case we define the following random variable X= (minutes) for a lab assistant to prepare the equipment for a certain experiment , and the distribution for X is given by:

The cumulative distribution function is given by:

The expected value is given by:

And we want to find the following probability:

And we can find this probability on this way:

And using the cumulative distribution function we got:

The probability that preparation is within 2 minutes of the mean time is 0.134
Given:
yesterday = 270
today = 216
yesterday's number of tickets sold is the basis of the percent of change. So, 270 is the 100%.
270 - 216 = 54 * value of the change in ticket sales
54/270 = 0.20 x 100% = 20% * percent of change
There was a 20% decrease in ticket sales.
Answer: 460.61
Step-by-step explanation: