Probability models and Sampling distribution

A geometric probability model follows a Bernoulli trial and:

• Has a set sample size n.
• Is looking for first success

What is the probability that a family doesn't have a baby girl until their third child?

• 0.125
• 0.15
• 0.05
• 0.88

Given that families continue to have children until they get a girl, what is the expected number of children per family?  Standard deviation?

• Expected Value = 2  St. Dev. =1.414
• Expected Value = 2  St. Dev. = 2
• Expected Value = 0.5  St. Dev. = 1.414
• Expected Value = 0.5 St. Dev. = 2

If the probability that a house in your neighborhood has a dog is 60%, what is the chance that you find a house with a dog before the fifth house?

• 0.97
• 0.99
• 0.02
• 0.04

Tags

CCSS.HSS.CP.A.2

It has been estimated that about 30% of frozen chicken contain enough salmonella bacteria to cause illness if improperly cooked. A consumer purchases 12 frozen chickens. What is the probability that the consumer will have more than 6 contaminated chickens? 

• .961
• .118
• .882
• .039

Of the 12 frozen chickens, how many would you expect to contain enough salmonella bacteria to cause illness if improperly cooked?  What is the standard deviation?

• Mean = 3.33   St. Dev. = 1.59
• Mean = 3.33  St. Dev. = 2.79
• Mean = 3.6       St. Dev. = 1.59
• Mean = 3.6        St. Dev. = 2.79

Is this binomial experiment? Shuffle a deck of 52 cards. Turn over the top card. Put the card back in the deck, shuffle again. Repeat the process 10 times. Let X = the number of aces you observe.

• Yes
• No, the trials are not independent.
• No, there are more than 2 outcomes

Tags

CCSS.HSS.CP.A.2

CCSS.HSS.CP.A.3

Which of the following is NOT an assumption of the Binomial distribution?

• All trials must be independent.
• Each trial must be classified as a success or a failure.
• All trials are dependent on each other.
• The number of successes in the trials is counted.

What happens to the shape of a sampling distribution of sample means as n increases?

• It becomes narrower and bimodal.
• It becomes narrower and more normal.
• It becomes wider and skewed right. 
• It becomes wider and more normal. 

The mean and standard deviation of a population are 400 and 40, respectively. Sample size is 25. 
What is the mean of the sampling distribution?

• 400
• 40
• 25
• 8