Problem 4: 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. Systematic 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.
Please answer the following questions:
A. In your own words, explain why this is an observational study. (5 points)
B. How many total female siblings are in this sample size? (5 points)
C. State the researchers' null hypothesis before the study was conducted. (5 points)
D. State the researchers' alternative hypothesis before the study was conducted. (5 points)
