Question

2. A small study (n=10) is designed to assess if there is an association between smoking in pregnancy and low birth weight. Low birth weight babies are those born less than 5.5 pounds. The following data represent the birth weights, in pounds, of babies born to mothers who reported smoking in pregnancy and those who did not.

Mother smoked in pregnancy                   5.0       4.2       4.8       3.3       3.9

Mother did not smoke during pregnancy    5.1       4.9       5.3       5.4       4.6

Is there a significant difference in birth weights between mother who smoked during pregnancy and those who did not? Apply the Mann Whitney U Test at a 5% level of significance.

Complete the table below.

2. cont.

Alpha= ________

N₁= ________

N₂= ________

Critical value U= ________

Smaller of U₁ and U₂ = ________

Based on comparing the Smaller of U₁ and U₂ to the Critical value which of the following is (are) true?

1. There is significant evidence at alpha=0.05 to show that the populations of birth weights in mothers who smoked in pregnancy and those who did not are not equal.
2. There is not significant evidence at alpha =0.05 to show that the populations of birth weights in mothers who smoked in pregnancy and those who did not are not equal.
3. There are not enough data points to reach a conclusion.
4. The tied value makes the analysis suspect.

Total Sample (Ordered Smallest to Largest) Smoked Ranks Mother Smoked in Pregnancy Mother Smoked Did Not Did Not Did Not Smoke Smoke a Smoke in n k Pregnancy 5.0 5.1 1 3.3 4.2 4.9 2 5.3 4.8 3 3.3 5.4 4 4,6 3.9 4.6 7 8 9 10 R2 U (n+1)_R,=. U2n (n2 +1) _R2= 2+- 2 + 2

Answer 1

olution o0.05 X numbes of obsevations Ni5 Y number o. obaeavations N5 For Fist Sample etr' be the Bum o TaNKs T: 18 Test Statigtics; Uming n,1/2.-T minniat 1)/ay-Kg 5xst 5(5+1) /A}-31 5-92 3 N, (Ng 4 1V/23 -RI Uye NN 555(51)/318 a5-3 lest static c U Bmmlle UxUy) Smaller (u,U) 2maller 3,8a) 3 Cortical vale for N, Ngtor at o o5 foM table of Man whithey calecitaled alue > criticol va luc, Fail to reject Null hypothegis gRDiflcant evidance at d 0 os Utest 9 ence Option 8: Thee s mb to show the populations oF binth weights in mothers oho SexoKGI tn poegnency and thase ubo chd noi- ane not eual.