Solution Found!
Putting It Together: Lupus Based on historical birthing
Chapter , Problem 40AYU(choose chapter or problem)
Problem 40AYU
Problem
Putting It Together: Lupus Based on historical birthing records, the proportion of males born worldwide is 0.51. In other words, the commonly held belief that boys are just as likely as girls is false. Systemic lupus erythematosus (SLE), or lupus for short, is a disease in which one’s immune system attacks healthy cells and tissue by mistake. It is well known that lupus tends to exist more in females than in males. Researchers wondered, however, if families with a child who had lupus had a lower ratio of males to females than the general population. If this were true, it would suggest that something happens during conception that causes males to be conceived at a lower rate when the SLE gene is present. To determine if this hypothesis is true, the researchers obtained records of families with a child who had SLE. A total of 23 males and 79 females were found to have SLE. The 23 males with SLE had a total of 23 male siblings and 22 female siblings. The 79 females with SLE had a total of 69 male siblings and 80 female siblings. Source: L.N. Moorthy, M.G.E. Peterson, K.B. Onel, and T.J.A. Lehman. “Do Children with Lupus Have Fewer Male Siblings” Lupus 2008 17:128-131, 2008.
(a) Explain why this is an observational study.
(b) Is the study retrospective or prospective? Why?
(c) There are a total of 23 + 69 = 92 male siblings in the study. How many female siblings are in the study?
(d) Draw a relative frequency bar graph of gender of the siblings.
(e) Find a point estimate for the proportion of male siblings in families where one of the children has SLE.
(f) Does the sample evidence suggest that the proportion of male siblings in families where one of the children has SLE is less than 0.51, the accepted proportion of males born in the general population? Use the α = 0.05 level of significance.
(g) Construct a 95% confidence interval for the proportion of male siblings in a family where one of the children has SLE.
Questions & Answers
QUESTION:
Problem 40AYU
Problem
Putting It Together: Lupus Based on historical birthing records, the proportion of males born worldwide is 0.51. In other words, the commonly held belief that boys are just as likely as girls is false. Systemic lupus erythematosus (SLE), or lupus for short, is a disease in which one’s immune system attacks healthy cells and tissue by mistake. It is well known that lupus tends to exist more in females than in males. Researchers wondered, however, if families with a child who had lupus had a lower ratio of males to females than the general population. If this were true, it would suggest that something happens during conception that causes males to be conceived at a lower rate when the SLE gene is present. To determine if this hypothesis is true, the researchers obtained records of families with a child who had SLE. A total of 23 males and 79 females were found to have SLE. The 23 males with SLE had a total of 23 male siblings and 22 female siblings. The 79 females with SLE had a total of 69 male siblings and 80 female siblings. Source: L.N. Moorthy, M.G.E. Peterson, K.B. Onel, and T.J.A. Lehman. “Do Children with Lupus Have Fewer Male Siblings” Lupus 2008 17:128-131, 2008.
(a) Explain why this is an observational study.
(b) Is the study retrospective or prospective? Why?
(c) There are a total of 23 + 69 = 92 male siblings in the study. How many female siblings are in the study?
(d) Draw a relative frequency bar graph of gender of the siblings.
(e) Find a point estimate for the proportion of male siblings in families where one of the children has SLE.
(f) Does the sample evidence suggest that the proportion of male siblings in families where one of the children has SLE is less than 0.51, the accepted proportion of males born in the general population? Use the α = 0.05 level of significance.
(g) Construct a 95% confidence interval for the proportion of male siblings in a family where one of the children has SLE.
ANSWER:
Answer :
Step 1:
To determine if this hypothesis is true, the researchers obtained records of families with a child who had SLE. A total of 23 males and 79 females were found to have SLE. The 23 males with SLE had a total of 23 male siblings and 22 female siblings. The 79 females with SLE had a total of 69 male siblings and 80 female siblings.
a). The researchers simply looked at records. There was no treatment imposed on the individuals in the study. So this is an observational study.
b). This study is Retrospective. Because retrospective study looks backwards and examines exposures to suspected risk in relation to an outcome.
c). There are a total of 23 + 69 = 92 male siblings in the study.
And female siblings are 22 + 80 = 102.
d).
e). To find a point estimate for the proportion of male siblings in families where one of the children has SLE.
Proportion of male
=