Final answer:
The p-value associated with these sample results b. is less than 0.05, indicating that there is sufficient evidence to suggest that the percentage of women over 50 diagnosed with osteoporosis is higher in the United States than in Mexico.
Step-by-step explanation:
To find the p-value associated with the sample results, we first need to calculate the test statistic. The test statistic for a test of proportions is calculated using the formula:
Z = (p - p₀) / sqrt((p₀(1-p₀))/n)
where p is the sample proportion, p₀ is the hypothesized population proportion, and n is the sample size. In this case, p = 40/200 = 0.2, p₀ = 20/200 = 0.1, and n = 200. Plugging these values into the formula, we get:
Z = (0.2 - 0.1) / sqrt((0.1(1-0.1))/200) = 2
Next, we need to find the p-value corresponding to a test statistic of 2. Using a standard normal distribution table, we can find that the p-value is approximately 0.0228. 
Since the p-value is less than 0.05, we reject the null hypothesis and conclude that there is sufficient evidence to suggest that the percentage of women over 50 diagnosed with osteoporosis is higher in the United States than in Mexico.