Summer Plans
| | Camp | No Camp | Total |
| :-------------------- | :--- | :------ | :---- |
| Swimming Lessons | 42 | 32 | 74 |
| No Swimming Lessons | 18 | 4 | 22 |
| Total | 60 | 36 | 96 |
Which is the joint relative frequency for school children who plan to attend camp and have swimming lessons? Round the answer to the nearest percent.
A. 4%
B. 19%
C. 33%
D. 44%
Answer (1)
Find the number of children who plan to attend camp and have swimming lessons: 42.
Find the total number of school children: 96.
Calculate the joint relative frequency: 96 42 × 100 = 43.75% .
Round to the nearest percent: 44% .
Explanation
Understand the problem and provided data We are given a table that shows the summer plans of school children. The table tells us how many children plan to attend camp, how many do not, how many have swimming lessons, and how many do not. We want to find the joint relative frequency for school children who plan to attend camp and have swimming lessons. This means we want to find the proportion of all school children who both plan to attend camp and have swimming lessons.
Calculate the joint relative frequency The number of children who plan to attend camp and have swimming lessons is 42. The total number of school children is 96. To find the joint relative frequency, we divide the number of children who plan to attend camp and have swimming lessons by the total number of school children: 96 42 .
Convert to percentage Now, we convert this fraction to a percentage by multiplying by 100: 96 42 × 100 = 43.75% .
Round to the nearest percent Finally, we round this percentage to the nearest percent, which gives us 44% .
State the final answer The joint relative frequency for school children who plan to attend camp and have swimming lessons is 44% .
Examples
Understanding joint relative frequencies can help in many real-world scenarios. For example, if you're a marketer trying to target a specific group of customers, you might want to know the joint relative frequency of people who use a certain product and also belong to a certain age group. This helps you tailor your marketing efforts more effectively. Another example is in healthcare, where you might want to know the joint relative frequency of people who have a certain disease and also exhibit a certain symptom. This can help doctors diagnose the disease more accurately.
