Probability

Find the mean of a binomial distribution with n=50 and p=0.4

• 50

• 4

• 20

• 10

Find the variance of a binomial distribution with 50 trials and p= 0.4

• 12

• 15

• 10

• 20

Find the z-score

x = 36 μ= 42 σ = 5

• 0.74

• 1.2

• -1.2

• 1.03

Bob is taking a 100 question test.  They have a 90 % probability of getting any one question correct.  WHICH IS THE CORRECT FORMULA TO FIND OUT THE PROBABILITY that they will answer EXACTLY 70  questions correctly?

• ₁₀₀C₇₀   ( 0.18  )³⁰ ( 0.90  )⁷⁰
  
• ₁₀₀C₇₀   ( 0.10  )³⁰ ( 0.90  )⁶⁰
• ₁₀₀C₇₀   ( 0.10  )³⁰ ( 0.90  )⁷⁰
• ₉₉C₇₀   ( 0.10  )³⁰ ( 0.90  )⁷⁰

Suppose a Poisson probability distribution with mean 5.1 provides a good approximation of the distribution of a random variable x. Find σ for x

• 2.2583

• 5.1000

• 26.0100

• 10.2000

The number of traffic accidents that occur on a particular stretch of road during a month follows a Poisson distribution with a mean of 7.4. Find the probability that fewer than three accidents will occur next month on this stretch of road.

• 0.0051

• 0.9368

• 0.0632

• 0.0219

If λ is equal to 25 then value of mean for exponential probability distribution is

• 0.4

• 0.08

• 0.07

• 0.04

If λ is equal to 8 then standard deviation of exponential probability distribution is

• 0.225

• 0.125

• 0.0156

• 0.425

If mean is equal to 4 then variance of exponential probability distribution is

• 0.0625

• 4

• 16

• 0.25

Which of the following statement is not true for an exponential distribution with parameter λ?

• mean = 1 / λ

• standard deviation = 1 / λ

• the distribution is a two-parameter distribution since the mean and standard deviation are equal

• the distribution is completely determined once the value of λ is known