Answer:
A) 0.35
B) Expected value = 37.4 passengers
C) Standard deviation = 1.24 passengers
Step-by-step explanation:
Part a.
The sum of all the probabilities should be 1, so we can calculate the missing probability as follows:
0.1 + 0.1 + 0.3 + x + 0.1 + 0.05 = 1
Solving for x, we get:
0.65 + x = 1
x = 1 - 0.65
x = 0.35
Then, the missing probability is 0.35
Part b.
The expected value is equal to the sum of each number of passengers multiplied by its respective probability, so:
E = 35(0.1) + 36(0.1) + 37(0.3) + 38(0.35) + 39(0.1) + 40(0.05)
E = 3.5 + 3.6 + 11.1 + 13.3 + 3.9 + 2
E = 37.4
Therefore, the expected value is 37.4 passengers
Part c.
To find the standard deviation, we first need to calculate the square of the difference between each value and the expected value, so
x (x - E)²
35 (35 - 37.4)² = 5.76
36 (36 - 37.4)² = 1.96
37 (37 - 37.4)² = 0.16
38 (38 - 37.4)² = 0.36
39 (39 - 37.4)² = 2.56
40 (40 - 37.4)² = 6.76
Then, the variance will be the sum of these values multiplied by its probability, so
Variance = 5.76(0.1) + 1.96(0.1) + 0.16(0.3) + 0.36(0.35) + 2.56(0.1) + 6.76(0.05)
Variance = 0.576 + 0.196 + 0.048 + 0.126 + 0.256 + 0.338
Variance = 1.54
Finally, the standard deviation is the square root of the variance
Standard deviation = √(Variance)
Standard deviation = √(1.54)
Standard deviation = 1.24
Therefore, the standard deviation is 1.24 passengers. and it is a measure of the dispersion, it says how far are the numbers from the mean.
Then, the answers are:
A) 0.35
B) Expected value = 37.4 passengers
C) Standard deviation = 1.24 passengers