## To calculate the probability of getting at least 80% correct on a True/False test, you can use the binomial distribution. The probability of getting a question correct is 1/2 (assuming an equal chance of selecting True or False). Let's say you have N questions on the test.

To start, calculate the probability of getting exactly 80% correct:

P(X = 0.8N) = (N choose 0.8N) * (1/2)^(0.8N) * (1/2)^(0.2N)

To calculate the probability of getting at least 80% correct, you need to sum up the probabilities of getting exactly 80%, 81%, 82%, and so on, up to N correct answers.

P(X >= 0.8N) = P(X = 0.8N) + P(X = 0.8N + 1) + P(X = 0.8N + 2) + ... + P(X = N)

To calculate this, you will need to use a calculator or a statistical software package that can perform binomial calculations.

If you want to repeat this process four more times, simply repeat the calculations for each set of questions, using the same formula. Keep in mind that the probabilities may vary depending on the number of questions and the desired percentage of correct answers.

Alternatively, you can use a binomial calculator or a spreadsheet program that has built-in functions for calculating binomial probabilities. Simply enter the number of questions and the desired percentage, and the software will provide you with the probability of achieving that percentage or higher.

Remember that these calculations assume random guessing and an equal chance of selecting True or False for each question. The actual probability may differ if the questions are not independent or if you have any prior knowledge that might influence your guesses.