Answer: E(X) = 30; Var[X] = 180
Step-by-step explanation: This is a <u>Bernoulli</u> <u>Experiment</u>, i.e., the experiment is repeated a fixed number of times, the trials are independents, the only two outcomes are "success" or "failure" and the probability of success remains the same, So, to calculate <em><u>Expected</u></em> <em><u>Value</u></em>, which is the mean, in these conditions:
r is number of times it is repeated
p is probability it happens
Solving:
E(X) = 30
<u>Variance</u> is given by:
Var[X] = 180
Expected Value and Variance of the number of times one must throw a die until 1 happens 5 times are 30 and 180, respectively.