Suppose that the duration of a particular type of criminal trial is known to be normally distributed with a mean of 21 days and a standard deviation of seven days. (a) In words, define the random variable X.
Continuous Probability Distributions
Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.
Normal Distribution
Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!
![Suppose that the duration of a particular type of criminal trial is known to be normally distributed
with a mean of 21 days and a standard deviation of seven days.
(a) In words, define the random variable X.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F97a7268c-f4b1-4c5f-be01-adfb29381cd9%2F7fc13057-aaa7-4207-938f-1d981d0bfaf6%2Fpmclpjo_processed.png&w=3840&q=75)
![(b) Find the z-score for a trial lasting 22 days.
(Round your answer to
three decimal places.)
(c) If one of the trials is randomly chosen, find the probability that it lasted at least 22 days.
(d) Shade the area corresponding to this probability in the graph below. (Hint: The x-axis is the z-
score. Use your z-score from part (b), rounded to one decimal place).
Shade: Left of a value
Click and drag the arrows to adjust the values.
-4
-3
-2 1 -1
2
3
-1.5
(e) twenty-five percent of all trials of this type are completed within how many days?](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F97a7268c-f4b1-4c5f-be01-adfb29381cd9%2F7fc13057-aaa7-4207-938f-1d981d0bfaf6%2F38louyl_processed.png&w=3840&q=75)
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