Final answer:
The probability of passing the test with at least a 70 percent is approximately 17.19%.
Step-by-step explanation:
To find the probability of passing the test with at least a 70 percent, we need to calculate the probability of getting 7, 8, 9, or 10 questions correct out of the 10-question quiz. Since each question has 2 options (true or false), the probability of guessing a question correctly is 1/2. Therefore, the probability of guessing 7, 8, 9, or 10 questions correctly is the sum of the probabilities of guessing each of these numbers correctly. This can be calculated using a binomial distribution formula or a calculator.
For example, using a binomial distribution calculator, if we assume a passing grade as 70 percent means getting 7 or more questions correct, the probability comes out to be approximately 0.1719, which is equivalent to 17.19%.