"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. 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.
c. There are a total of 23+69=92 male siblings in the study. How many female siblings are in the study?

Verified step by step guidance

1. Identify the number of female siblings for each group: the 23 males with SLE and the 79 females with SLE.
2. From the problem, the 23 males with SLE have 22 female siblings.
3. The 79 females with SLE have 80 female siblings.
4. Add the female siblings from both groups together to find the total number of female siblings: \$22 + 80$.
5. This sum gives the total number of female siblings in the study.

Key Concepts

Basic Arithmetic and Data Summation

Understanding how to sum quantities correctly is essential for analyzing data sets. In this question, adding the number of male siblings from different groups helps find the total male siblings. Similarly, summing female siblings requires combining counts from multiple categories to get an overall total.

Categorical Data Organization

Data is often grouped by categories such as gender or disease status. Recognizing how data is organized—like siblings of males with SLE versus siblings of females with SLE—helps in correctly interpreting and combining the numbers for analysis.

Contextual Understanding of the Problem

Grasping the biological and research context, such as the sex ratio and its relation to lupus, is important to understand why the data is collected and what the question aims to find. This helps in focusing on relevant data points and interpreting results meaningfully.