Mean Variance and Standard Deviation of Binomial Distribution

It is computed by getting the weighted average of all possible values of a random variable.

• mean

• variance

• standard deviation

• binomial distribution

What is the average of the squared deviations from the mean?

• mean

• variance

• Standard deviation

• z- score

Find the standard deviation of a binomial distribution with n=50 and p=0.4 (Round to the nearest tenth)

• 4.2

• 3.5

• 12.0

• 6.2

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

• 50

• 4

• 20

• 10

A binomial event has n = 60 trials. The probability of success on each trial is 0.4. Let X be the count of successes of the event during the 60 trials. What are mean X and standard deviation X?

• 24; 3.79

• 24; 14.4

• 4.9; 3.79

• 4.9; 14.4

It is known that about 90% of the widgets made by Buckley Industries meet specifications.  Every hour a sample of 18 widgets is selected at random for testing and the number of widgets that meet specifications is recorded.  What is the approximate mean and standard deviation of the number of widgets meeting

• μ = 1.62; σ = 1.414

• μ = 1.62; σ = 1.265

• μ = 16.2; σ = 1.62

• μ = 16.2; σ = 1.273

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

• 12

• 15

• 10

• 20

• Mean = 5.5 
  Variance =  1.57
  Standard Deviation = 2.475
• Mean = 5.0 
  Variance = 5.5
  Standard Deviation = 2.345
• Mean = 10
  Variance = .55
  Standard Deviation = .45
• Mean = 5.5 
  Variance = 2.475 
  Standard Deviation = 1.57 

• Mean =7.92
  Variance =  2.6928
  Standard Deviation = 1.64
• Mean = 12 
  Variance = .66
  Standard Deviation = .44
• Mean = 12
  Variance = 7.92
  Standard Deviation = 2.814
• Mean =7.92
  Variance = 1.64
  Standard Deviation = 2.6928 

• Not a binomial experiment
• Yes. n = 8
  p = .85 
  q = .15
   x = 0, 1, 2, 3, 4, 5, 6, 7, 8
• Yes. n = 8
  p = .15 
  q = .85
   x = 0, 1, 2, 3, 4, 5, 6, 7, 8
• Yes. n = 8
  p = .85 
  q = .15
   x = 8