Stat HW 4.1
What is a discrete probability distribution? What are the two conditions that determine a probability distribution?
A discrete probability distribution lists each possible value a random variable can assume, together with its probability.
Decide whether the random variable x is discrete or continuous "x represents the tension at which a randomly selected guitar's strings have been strung"
Continuous
Determine whether the random variable is discrete or continuous. "The amount of rain in City B during April"
Continuous
Determine whether the random variable is discrete or continuous. "The exact time it takes to evaluate 27 +72"
Continuous
Determine whether the random variable is discrete or continuous. "The square footage of a house"
Continuous
Determine whether the random variable is discrete or continuous. "The time required to download a file from the internet"
Continuous
Determine whether the random variable is discrete or continuous. "The weight of a t-bone steak"
Continuous
Decide whether the graph represents a discrete random variable or a continuous random variable. "The length of time students use a computer each week"
Continuous, because the length of time is a random variable that is uncountable.
Determine whether the random variable is discrete or continuous. "The # of bald eagles in the country"
Discrete
Determine whether the random variable is discrete or continuous. "The # of free-throw attempts before the first shot it made"
Discrete
Determine whether the random variable is discrete or continuous. "The # of hits to a website in a day"
Discrete
Determine whether the random variable is discrete or continuous. "The # of light bulbs that burn out in the next week in a room with 13 bulbs"
Discrete
Determine whether the random variable is discrete or continuous. "The # of people in a restaurant that has a capacity of 200"
Discrete
Determine whether the random variable is discrete or continuous. "The # of points scored during a basketball game"
Discrete
Determine whether the random variable is discrete or continuous. "The # of statistics students now reading a book"
Discrete
Decide whether the graph represents a discrete random variable or a continuous random variable. "The home attendance for football games at a university"
Discrete, because home attendance is a random variable that is countable.
What are the two conditions that determine a probability distribution?
The probability of each value of the discrete random variable is between 0 and 1, inclusive, and the sum of all the probabilities is 1.
T/F? The expected value of a random variable can never be negative.
True