Mr. Stevenson is paying a company to fence in a rectangular portion of his yard for a play area. The area will be 7 yards long and 11 yards wide. The contractor is planning to install posts 1 yard apart, with one post at each corner. How many posts are needed?

Rachel is studying the population of a particular bird species in a national park. she observes every 10th bird of that species that she can find in the park. her conclusion is that the birds living in the park who belong to that species generally feed on insects. rachel's sample is . based on the sample she picked, rachel's generalization is