WGU statistics Exam Questions and Answers 100% Pass

WGU statistics Exam Questions and Answers 100% Pass The probability of any event is between one and o. What is the equation for this? For any event A, 0 ≤ P(A) ≤ 1. The sum of all possible probabilities is___? One, the equation is :P(S) = 1 What is the complement rule? or the probability that an event does not occur is 1 minus the probability that it does occur. P(not A) = 1 - P(A) In probability, "OR" means either one or the other or both. P(A or B) = P(event A occurs or event B occurs or both occur) Two events that cannot occur at the same time are called disjoint or mutually exclusive The Addition Rule for Disjoint Events: If A and B are disjoint events, then P(A or B) = P(A) + P(B). P(A and B) = P(event A occurs and event B occurs) The idea of disjoint events is is about whether or not it is possible for the events to occur at the same time The idea of independent events is about whether or not the events affect each other in the sense that the occurrence of one event affects the probability of the occurrence of the other If A and B Disjoint A and B can not be indepentdent If A and B are two independent events (Multiplication Rule) P(A and B) = P(A) * P(B). if A, B and C are three independent events, P(A and B and C) = P(A) P(B) P(C) The Complement Rule, P(A) = 1 - P(not A), P(L) = 1 - P(not L) = 1 - P(not O1 and not O2 and not O3 and not O4 and not O5 and not O6 and not O7 and not O8 and not O9 and not O10). Applying the Multiplication rule:Now, using the multiplication rule, = 1 - (.56 .56 .56 .56 .56 .56 .56 .56 .56 * .56) = 1 - .003 = .997. P(at least one person chosen has blood type O) P((O and O) or (O and not O) or (not O and O)) = (.44 .44) + (.44 .56) + (.56 * .44) = .6864. If A and B are disjoint events - P(A and B)= 0 The General Addition Rule states that for any two events, P(A or B) = P(A) + P(B) - P(A and B) When each of two outcomes has two possible values (yes/no), there are four possible combinations altogether, which correspond to the four possible outcomes. How do we build a two-way table of probabilities? Horizontally, A, not A and total, Vertically, B. not B and total In a two-way table of probabilities, what is the total of all outcomes (lower right corner?) 1 Two events A and B are independent if any one of the following hold: P(B | A) = P(B) P(A | B) = P(A) P(B | A) = P(B | not A) P(A and B) = P(A) * P(B) In general, another method for checking the independence of events A and B is to compare P(A and B) to P(A) * P(B). If the two are equal, then A and B are independent, otherwise the two are not independent. "one in every thousand people (0.001) of all individuals are infected with HIV (H) - give equasion P(H) = .001 If someone actually has HIV, the probability of testing positive is .95" (H) give equasion P(T | H) = .95 Use the General Multiplication Rule to find the probability that someone chosen at random from the population has HIV and tests positive. (H is HIV positive and probability of HIV+ test accuracy is .95) P(H and T) = P(H) * P(T given H) = .001 x .95 = .00095. IF person is HIV positive and test accuracy is .95, what are the chances that that person will test negative (give equation) P(not T | H) = 1 - P(T | H) = 1 - .95 = .05. In a probability tree, the probabilities in the first branch-off are non-conditional probabilities In a probability tree,second branch-off are conditional probabilities. In a probability tree, the second thing to note is that probabilities of branches that branch out from the same point always add up to one In a probability tree, symbolically, V = (C and V) or (not C and V). Thus, the overall probability of taking the vacation is P(V) = P( (C and V) or (not C and V) ). In a probability tree, overall probability of V, in the event of C or not C is determined by what sequence of equasions? Applying the Addition Rule for Disjoint Events, we have P(V) = P(C and V) + P(not C and V). Applying the General Multiplication Rule to each term, we have P(V) = P(C) P(V | C) + P(not C) P(V | not C) A histogram is a display of a single quantitative variable A scatterplot is a display of two quantitative variables A two way table is a display of the relationship of two variables that are both categorical The appropriate display for the relationship between two variables based upon their type (Quantitative or categorical) and their role (explanatory or response) is side by side box plots What are the two simple graphical displays for visualizing the distribution of categorical data? The pie chart and the bar chart How does one calculate the standard deviation?