An ecologist wants to estimate the population of a rare wildflower species in a nature reserve. The reserve is partitioned into a grid of 500 distinct squares, each measuring 10 m×10 m10\text{ m} \times 10\text{ m}10 m×10 m. The ecologist assigns a unique number from 1 to 500 to each grid square and uses a random number generator to choose 40 of these squares to survey.
Which of the following best identifies the sampling frame in this scenario?
The 40 grid squares chosen by the random number generator to be surveyed
A single 10 m×10 m10\text{ m} \times 10\text{ m}10 m×10 m grid square
The list of numbers from 1 to 500 representing all the grid squares
The entire population of wildflowers within the nature reserve
644 exam-style questions on OCR A Level Psychology Research methods and techniques. Each one has a worked solution and a mark scheme showing where the marks go.