An investigator wants to show that first-born children score higher on IQ tests

Question

An investigator wants to show that first-born children score higher on IQ tests than second-borns. He takes a simple random sample of 400 two-child families in a school district, both children being enrolled in elementary school. He gives these children the WISC vocabulary test, with following results: The 400 first-borns average 29 and their SD is 10. The 400 second-borns average 28 and their SD is 10. Does the result support the research hypothesis?

Explanation / Answer

H0: u1=u2 H1 : u1>u2 test statistic = ((X1bar-X2bar)- (0)/Sp*(sqrt(1/n1 + 1/n2)) Where Sp is pooled variance with Sp^2 = [ (n1-1)S1^2 + (n2-1)S2^2 ]/ [n1+n2-2] Sp^2 = 100 Sp = 10 n1= 400 n2= 400 x1bar=29 x2bar=28 s1=10 s2=10 T = 1.414 this follows t(n1+n2-2) now t18 at 5% is 1.734 SO test statistic is less than critical value ...hence null hypothesis can’t be rejected.. So there is not enough support to suggest the research hypothesis so we cant say that first born child scores more than 2nd born child

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.