Answer:
(a) The probability distribution is valid.
(b) The probability that x = 30 is 0.30.
Step-by-step explanation:
The probability distribution of the random variable <em>X</em> is:
<em> x</em>: 20 | 25 | 30 | 35
f (<em>x</em>): 0.20 | 0.15 | 0.30 | 0.35
(a)
The properties of a probability distribution are:
All the probability value are more than 0 and less than 1.
Compute the sum of all the probabilities as follows:
The sum of all probabilities is 1.
Thus, the probability distribution is valid.
(b)
Consider the probability distribution table.
The probability of <em>X</em> = 30 is,
P (X = 30) = 0.30.
Thus, the probability that x = 30 is 0.30.
Answer:
0.56 is the required probability.
Step-by-step explanation:
Time for which signal shows green light = 4 minutes
Time for which signal shows yellow light = 10 seconds
Time for which signal shows red light = 3 minutes
To find:
Probability that the signal will show green light when you reach the destination = ?
Solution:
First of all, let us convert each time to same unit before doing any calculations.
Time for which signal shows green light = 4 minutes = 4 60 seconds = 240 seconds
Time for which signal shows yellow light = 10 seconds
Time for which signal shows red light = 3 minutes = 3 60 seconds = 180 seconds
Now, let us have a look at the formula for probability of an event E:
Here, E is the event that green light is shown by the signal.
Number of favorable cases mean the time for which green light is shown and Total number of cases is the total time <em>(Time for which green light is shown + Time for which Yellow light is shown + Time for which red light is shown)</em>
So, the required probability is: