Answer:
174
Step-by-step explanation:
L = 68
W=19
Use the formula given:
2 x 68 + 2 x 19 = 174
The probability of Erin not having a heart attack according to her family history would be 30%.
The probability of the test predicting correctly is 67%.
Therefore, the probability of the test correctly predicting that Erin will not have a heart attack would be (0.30)(0.67) = 0.201 or 20.1%.