Answer :
Answer:
a) The number of people expected to pass is 220
b) Standard deviation is 10
c) After a great many days, regarding the Empirical Rule, on about 95% of these days, the number of people passing will be as low as 200 and as high as 240.
Step-by-step explanation:
a) The number of people expected to pass = np = 400*0.55 = 220
b) Standard deviation = \sqrt{npq} = \sqrt{400*0.55*0.45} = 10
c) Regarding the empirical rule, 95% of the observations lie within 2 SD from the mean. Therefore,
Lower bound = 220 - 2*!0 = 200
Upper bound = 220 + 2*10= 240
After a great many days, regarding the Empirical Rule, on about 95% of these days, the number of people passing will be as low as 200 and as high as 240.
After a great many days, regarding the Empirical Rule, on about 95% of these days, the number of people passing will be as low as 200 and as high as 240.
It is given that
55 % of people pass the drivers' road test and 400 people independently take the test.
So, the number of people who are expected to pass = 400*0.55 = 220
What is the standard deviation formula for binomial distribution?
Standard deviation is the square root of variance i.e [tex]\sqrt{npq}[/tex]
Where n is no of trials while p and q are complementary probabilities.
Standard deviation =[tex]\sqrt{400*0.55*0.45}[/tex] = [tex]\sqrt{99}[/tex] =9.95≈10
Two standard deviation below the mean = 220-2*10 =200
Two standard deviation above the mean= 220 + 2*10= 240
Therefore, After a great many days, regarding the Empirical Rule, on about 95% of these days, the number of people passing will be as low as 200 and as high as 240.
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