Statistics and Probability_2

Let the probability experiment be tossing a coin thrice.

Let the random variable X be the number of tails. What is the probability distribution of X?

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• 
• 
• 

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.

• No, some of probabilities are not between 0 and 1 inclusive

• No, the sum of all the probabilities is not 1.

• Yes, because the distribution is symmetric

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.
• No, all probabilities are not be between 0 and 1 inclusive
• No, the sum of all the probabilities is not 1.
• Yes, because the distribution is symmetric

Determine which of the following distribution is NOT a probability distribution.

• A

• B

• C

• D

3. Which of the following is a property of a probability distribution?

• The sum of all probabilities must equal 0.

• Each probability must be greater than 1.

• The probability of each value of the random variable must be between or equal to 0.

• The probabilities can be any value between -1 and 1.

It consists of the values a random variable can assume and the corresponding probabilities of the values.

• random variable

• continuous random variable

• discrete random variable

• discrete probability distribution

The table represents the probability of guessing correct on a 5 question true-false quiz.  Find the probability for at least 4 questions correct.

• .03125
• .15625
• .3125
• .1875

The table above shows the number of cell phones per household in a small town. Find the mean round to the nearest hundredth.

• 2.80

• 2.93

• 0.10

• 0.14

In a certain community, 30% of households have 1 child, 43% have 2 children, and 27% have 3 children. If a household is selected at random, what is the expected number of children in that household?

• 2.00

• 2.13

• 1.97

• 1.27