what is a simple random sample 
a simple random sample is a subset of a statistical population in which each member of the subset has an equal probability of being chosen a simple random sample is meant to be an unbiased representation of a group investopedia madelyn goodnightunderstanding a simple random sampleresearchers can create a simple random sample using a couple of methods with a lottery method each member of the population is assigned a number after which numbers are selected at random an example of a simple random sample would be the names of 25 employees being chosen out of a hat from a company of 250 employees in this case the population is all 250 employees and the sample is random because each employee has an equal chance of being chosen random sampling is used in science to conduct randomized control tests or for blinded experiments the example in which the names of 25 employees out of 250 are chosen out of a hat is an example of the lottery method at work each of the 250 employees would be assigned a number between one and 250 after which 25 of those numbers would be chosen at random because individuals who make up the subset of the larger group are chosen at random each individual in the large population set has the same probability of being selected in most cases this creates a balanced subset that carries the greatest potential for representing the larger group as a whole a manual lottery method can be quite onerous for larger populations selecting a random sample from a large population usually requires a computer generated process the same methodology as the lottery method is used only the number assignments and subsequent selections are performed by computers not humans with a simple random sample there has to be room for error represented by a plus and minus variance sampling error for example if in a high school of 1 000 students a survey is taken to determine how many students are left handed random sampling can determine that eight out of the 100 sampled are left handed the conclusion would then be that 8 of the student population of the high school are left handed when in fact the global average would be closer to 10 the same is true regardless of the subject matter a survey on the percentage of the student population that has green eyes or a physical disability would result in a mathematical probability based on a simple random survey but always with a plus or minus variance the only way to have a 100 accuracy rate would be to survey all 1 000 students which while possible would be impractical although simple random sampling is intended to be an unbiased approach to surveying sample selection bias can occur when a sample set of the larger population is not inclusive enough representation of the full population is skewed and requires additional sampling techniques 