In the 1990s, it was generally believed that genetic abnormalities affected abou
ID: 3048160 • Letter: I
Question
In the 1990s, it was generally believed that genetic abnormalities affected about 31% of a large nation's children. Some people believe that the increase in the number of chemicals in the environment has led to an increase in the incidence of abnormalities, which could have important implications for health insurance companies. A recent study examined 387 randomly selected children and found that 134 of them showed signs of a genetic abnormality. (a) Which hypotheses should be used to test if the proportion of genetic abnormalities has increased in recent years?State the Z test statistic. (Round your answer to three decimal places.) State the p-value. (Round your answer to four decimal places.
Explanation / Answer
Hypothesis to be tested: Is p'>p
p' = 134/387 = 0.346
p= 31% = 0.31
z = (p' - p) / sqrt(p(1-p)/n)
= (0.346-0.31)/sqrt(0.31*0.69/387)
z = 1.531
Thus p-value = P(Z>1.53) = 1 - 0.9370 = 0.0630