Statistical Analysis of Group Work Problems: Hypothesis Testing and Regression, Assignments of Statistics

Download Statistical Analysis of Group Work Problems: Hypothesis Testing and Regression and more Assignments Statistics in PDF only on Docsity! Solutions to group work problems: Chapter 9 1a) H0 :d=0vsHA :d0 d=y1−y2 , d=1.6 , sd=3.36 , ts=.95 ,pv=.198>.05, so null hypothesis not rejected, no evidence that diet works 1 b) (-3.06, 6.26) CI contains 0, so we can't reject null hypothesis as stated in part a. 2a p−value=2P N≥6 =2(.25391)=.50782, P N≥6=1−binomcdf 9,.5,5 2b p-value=.25391 3. H0 :d=0noeffect vsH A: d≠0 effect  , Bs=N=6 , p−value=2P N≥6 =.03125<.05, so we reject null hypothesis, there is evidence for alternative hypothesis ( P N≥6=1−binomcdf 6,.5,5 ) Chapter 10 1. H0 :p=.5vsHA :p≠.5 , where p=proportion of plants with one leaf E=.5(135)=67.5 for both classes s 2 =1.252 pv=.2632>.05 Do not reject null hypothesis, no evidence that two types have different probability of occurrence. 2. H0 :p=.3vsHA :p.3 , p=mortality rate after 1970 O: 45 160 E: 61.5 143.5 s 2 =6.33 , p-value=.006<.05 Reject null hypothesis, evidence that mortality rate decreased since 1970 3. H0 : all choices are equally likely (random) vs H A : not all choices are equally likely all E=.25(50)=12.5 s 2 =4.88 , pv=.181>.05 Do not reject null hypothesis, choices are randomly selected (all with equal probability) 4. a) H0 : survival rate is the same for both groups p1=p2 vs H A : survival rates are different in two groups p1≠p2 O: 78, 66, 76, 98 E: 69.7, 74.3, 84.3, 89.7 s 2 =3.47 , p-value=.062 Do not reject null, no evidence for alternative.