Final answer:
a) The probability a student receives high scores on tests and is not involved in at least one extracurricular activity is 0.4 or 40%. b) P(E|T) represents the conditional probability that a student is involved in at least one extracurricular activity given that they received high scores on tests. The value of P(E|T) is 0.5 or 50%.
Step-by-step explanation:
a) The probability a student receives high scores on tests and is not involved in at least one extracurricular activity can be represented as P(T and not E). The formula for calculating this probability is P(T and not E) = P(T) - P(T and E). From the given information, we know that P(T) = 0.8 and P(T and E) = 0.4. Therefore, P(T and not E) = 0.8 - 0.4 = 0.4, or 40%.
b) P(E|T) represents the conditional probability that a student is involved in at least one extracurricular activity given that they received high scores on tests. The formula for calculating this probability is P(E|T) = P(T and E) / P(T). From the given information, we know that P(T and E) = 0.4 and P(T) = 0.8. Therefore, P(E|T) = (0.4 / 0.8) = 0.5, or 50%.