At what age do babies learn to crawl? Does it take longer to learn in the winter when babies are often bundled in clothes that restrict their movement? Data were collected from parents who brought their babies into the University of Denver Infant Study Center to participate in one of a number of experiments between 1988 and 1991.Parents reported the birth month and the age at which their child was first able to creep or crawl a distance of 4 feet within 1 minute.The resulting data were grouped by month of birth: January,May,and September: Crawling age is given in weeks.Assume the data represent three independent simple random samples,one from each of the three populations consisting of babies born in that particular month,and that the populations of crawling ages have Normal distributions. A partial ANOVA table is given below. Multiple comparison procedures are going to be used to calculate simultaneous confidence intervals for all pairwise comparisons using the Bonferroni method.
For  = 0.10,the value of t^** is 2.16.What would be the 90% confidence interval for the difference between May and September using the Bonferroni method?

A) (-9.39,-1.11)
B) (-9.22,-1.28)
C) (1.28,9.22)
D) (3.29,7.21)

Question

At what age do babies learn to crawl? Does it take longer to learn in the winter when babies are often bundled in clothes that restrict their movement? Data were collected from parents who brought their babies into the University of Denver Infant Study Center to participate in one of a number of experiments between 1988 and 1991.Parents reported the birth month and the age at which their child was first able to creep or crawl a distance of 4 feet within 1 minute.The resulting data were grouped by month of birth: January,May,and September:    = 0.10,the value of t **  is 2.16.What would be the 90% confidence interval for the difference between May and September using the Bonferroni method? A) (-9.39,-1.11)  B) (-9.22,-1.28)  C) (1.28,9.22)  D) (3.29,7.21)  class=answers-bank-image d-block rel=preload > Crawling age is given in weeks.Assume the data represent three independent simple random samples,one from each of the three populations consisting of babies born in that particular month,and that the populations of crawling ages have Normal distributions. A partial ANOVA table is given below.    = 0.10,the value of t **  is 2.16.What would be the 90% confidence interval for the difference between May and September using the Bonferroni method? A) (-9.39,-1.11)  B) (-9.22,-1.28)  C) (1.28,9.22)  D) (3.29,7.21)  class=answers-bank-image d-block rel=preload > Multiple comparison procedures are going to be used to calculate simultaneous confidence intervals for all pairwise comparisons using the Bonferroni method.For    = 0.10,the value of t **  is 2.16.What would be the 90% confidence interval for the difference between May and September using the Bonferroni method?A) (-9.39,-1.11)B) (-9.22,-1.28)C) (1.28,9.22)D) (3.29,7.21)

yaratha pooja · Accepted Answer

Final Answer : B, Explanation :  The relevant row in the ANOVA table is for SS(B) which has a value of 6832.29 and df(B) which has a value of 2. The MS(B) is therefore 3416.145. The Bonferroni method requires that we use a significance level of 0.10/3 = 0.0333. The standard error of the difference between the means of May and September is sqrt{[s^2/n1]+[s^2/n2]} = sqrt{[687.938/66]+[759.198/66]} = sqrt(20.450) = 4.52 where s^2 is the mean square error from the ANOVA table, and n1 and n2 are the sample sizes for May and September, respectively. The difference between the means is 5.2 - 6.7 = -1.5. The 90% Bonferroni confidence interval for the difference between the means is therefore -1.5 +/- 2.16(4.52) or (-9.22,-1.28).

Definitions

Learning Objectives

Learning Objectives

Related questions