Question

1. there are 300 seventh - grade students at amayas school. a random sample of seventh - graders were asked if they usually buy lunch from the cafeteria or bring lunch from home. the results showed that 9 students in the sample buy lunch and 16 students bring lunch.

write an expression you can use to estimate the number of seventh - grade students who do not buy lunch from the cafeteria.

+ - • ÷

\\( \frac { 9 } { 25 } \\) \\( \frac { 16 } { 25 } \\) \\( \frac { 9 } { 16 } \\) 300

Explanation:

Step1: Calculate the total number of students in the sample

The total number of students in the sample is \(9 + 16=25\)

Step2: Find the proportion of students who do not buy lunch

The number of students who do not buy lunch (bring lunch) is \(16\). The proportion is \(\frac{16}{25}\)

Step3: Set up the expression to estimate the number of non - cafeteria - buying students in the whole grade

We use the proportion from the sample to estimate for the whole population of \(300\) students. The expression is \(\frac{16}{25}\times300\)

Answer:

\(\frac{16}{25}\times300\)