Question

As part of a curriculum review, the psychology department would like to select a simple random sample of 20 of last year's 140 graduates to obtain information on how graduates perceived the value of the curriculum. Describe two different methods that might be used to select the sample.

Short answer

The two methods for obtaining a simple random sample from 140 graduates could be the Random Number Generator method and the Lottery method. In both methods, each student is assigned a unique identifier (number) and then a selection is made either digitally (random number generator) or physically (lottery method) which ensures a fair and unbiased sampling of the graduates.

Step-by-step solution

Method 1: Random Number Generator method

A random number generator could be used to select the 20 graduates. Each student would be numbered 1 to 140. These numbers would then be placed into the random number generator. For example, on a spreadsheet software, a range of random numbers between 1 and 140 can be generated. Then, select the first 20 unique numbers and the corresponding students would be the ones included in the sample.

Method 2: Lottery method

The Lottery method or 'Hat-and-draw' method could be another approach. Here, each student is assigned a distinct number from 1 to 140. The numbers are then written on identical pieces of paper or cards. All of these are placed in a large container or bag, mixed up, and then 20 numbers are drawn out. This is equivalent to a random sample because each number (student) has an equal chance of being selected.