To find the empirical probability of David's incorrect responses, we need to first calculate the number of incorrect responses.
1. David got 45 out of 70 items correct, so the number of incorrect responses is:
Total responses - Correct responses = 70 - 45 = 25
2. Now, we can find the empirical probability of his incorrect responses by dividing the number of incorrect responses by the total number of responses:
Empirical Probability = Number of incorrect responses / Total number of responses
Empirical Probability = 25 / 70
3. Simplifying the fraction 25/70 gives us the simplest form:
Empirical Probability = 5 / 14
Therefore, the empirical probability of David's incorrect responses is 5/14.