Use the sign test for the claim involving nominal data. Gender Selection? The Genetics and IVE Institute conducted a clinical trial of its methods for gender selection. As of this writing, 239 of 291 babies born to parents using the YSORT method were boys. Use a 0.01 significance level to test the claim that the YSORT method has no effect.
Solution 13BSC Step 1 Let us denote ‘p’ as the proportion of boys i.e., Proportion of boys (p) = 1 = 0.5. 2 By using = 0.01 level of significance to test the claim that the YSORT method has no effect since 239 of 291 babies born to parents using the YSORT method were boys i.e., p > 0.5. The Hypotheses can be expressed as H0 p = 0.5 (proportion of boys = 0.5) H1 p > 0.5 (more babies babies born to parents using the YSORT method were boys) Step 2 Let us denote negative sign (-) for boys and positive sign (+) for girls, we have 239 negative signs and 52 positive signs. Now we need to determine whether 52 girls are low to be significant, hence we make use of left tailed test. Positive signs = 52 Negative signs = 239 Number of ties = 0 Now, the Test Statistic is the less frequent sign i.e., positive sign = 52 Therefore, x = 52 is the required value of test statistic. Hence for sign test the required sample size used is 291 i.e., n = 52 + 239 = 291 which is greater than 25 (n 25).