Final answer:
To conduct a hypothesis test to evaluate the claim that IQ scores are higher in individuals with low lead exposure, a two-tailed Student's t-test can be used. The null hypothesis (H0) states that there is no difference in IQ scores between low and high lead exposure groups. Using the given data, the t-value and p-value can be calculated to make conclusions.
Step-by-step explanation:
To conduct a hypothesis test to evaluate the claim that IQ scores are higher in individuals with low lead exposure, we can use a two-tailed Student's t-test. The null hypothesis (H0) would state that there is no difference in IQ scores between low and high lead exposure groups, while the alternative hypothesis (H1) would state that IQ scores are higher in individuals with low lead exposure.
Using the given data for low lead levels (x = 92.9, s = 15.3, n = 78) and high lead levels (x = 86.9, s = 9.0, n = 21), we can calculate the t-value using the formula:
t = (x1 - x2) / sqrt((s1^2 / n1) + (s2^2 / n2))
With the calculated t-value, we can then find the corresponding p-value using a t-distribution table or a statistical calculator. If the p-value is less than the significance level (α), which is 0.05 in this case, we would reject the null hypothesis and conclude that there is evidence to support the claim that IQ scores are higher in individuals with low lead exposure.