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(Question from Mathematics Standard Level for the IB Diploma) The probability distribution of a random variable X is given by P(X=x) = kx(4-x), where x = 1, 2, 3. a) Find the value of k. We have 3 values in our sample space: 1, 2 and 3. The corresponding probability distribution is: P(1) = k(1)(4-1) = 3k…

What the heck is Expected Value? It is exactly what you would think it is. If you conduct an experiment, the expected value is how many times a certain event is expected to happen. For example, if you roll a die 6 times, how many times do you expect to roll a 2?   How…

In this section, we will only be dealing with discrete probability distributions. Discrete probability distributions deal with discrete random variables. We will use simple examples where the sample space is clear, so that it becomes easy to calculate the probability… that is, if you know what you are doing 😉.   What the Heck is a Probability…

(Question from Mathematics for the international student Mathematics SL. Third Edition) For each of the following: identify the random variable being considered give possible values for the random variable indicate whether the variable is continuous or discrete   a) To measure the rainfall over a 24-hour period in Singapore, the height of water collected in…

What the heck is a random variable?   It is not a variable in the same sense that you have seen before in equations such as y = 2x + 1. A random variable is the number of possible outcomes (in number form) which could occur from a random experiment. Let’s unpack what that definition means. The first…

(Question from Mathematics for the international student Mathematics SL. Third Edition) Consider tossing three coins simultaneously. The random variable under consideration is the number of heads that could result. a) List the possible values of X. This question may seem a bit confusing because they don’t define what X is. From the context, we can…