What is the probability that she will makes 4 sales before the seventh person she approaches?

Let X represent the difference between the number of heads and the number of tails obtained when a coin is tossed n times.
What are the possible values of X?

Based on the Normal model N(100, 16) describing IQ scores, what percent of peoples

Let X be a normal random variable with mean 12 and variance 4. Find the value of c such that P{X>c}=.10.

Each year, a company either makes a profit or takes a loss. If the company made a profit the year before, they will make a profit with probability 0.7. If they took a loss the year before, they will make a profit with probability 0.3. What is the long-run probability the company will make a profit?

Sue and Ann are taking the same English class but they do not study together, so whether one passes will be Independent of whether the other passes. In other words, “Sue passes and “Ann passes” are assumed to be independent events. The probebiity that Sue passes English is 0.8 and the probablity that Ann passes English is 0.75 Whats the probabilty both girls pass English?

Suppose that you toss a coin three times and roll three dice. What is the probability of obtaining two tails, one five, and at least one dice roll of less than three?

The game of Clue involves 6 suspects, 6 weapons, and 9 rooms. One of each is randomly chosen and the object of the game is to guess the chosen three. (a) How many solutions are possible? In one version of the game, the selection is made and then each of the players is randomly given three of the remaining cards. Let S, W, and R be, respectively, the numbers of suspects, weapons, and rooms in the set of three cards given to a specified player. Also, let X denote the number of solutions that are possible after that player observes his or her three cards. (b) Express X in terms of S, W, and R. (c) Find E[X]