Edexcel A Level Mathematics (Statistics) Paper 31 Mark Scheme June verified correct answers

Edexcel A Level Mathematics (Statistics) Paper 31 Mark Scheme June verified correct answers Disadvantages of systematic sampling - correct answer-A sampling frame is needed+ It can introduce bias if the sampling frame is not random What is stratified sampling? - correct answer-Dividing the population into mutually exclusive groups and then taking random samples from each Population - correct answer-The whole set of items that are of interes Census - correct answer-An observation or measurement of every member of a population Subset - correct answer-A sample of the population for a study Sample - correct answer-A selection of observations taken from a subset of the population Advantages of a census - correct answer-It should give a completely accurate result Disadvantages of a census - correct answer-Time consuming and expensive + Cannot be used when the testing process destroys the item +Hard to process large quantity of data Advantages of a sample - correct answer- Less time consuming and expensive than a census + Fewer people have to respond + Less data to process than in a census Disadvantages of a sample - correct answer-The data may not be as accurate + The sample may not be large enough to give information about small sub-groups of the population + Risk of incomplete conclusion due to low accuracy Statistics - correct answer-A branch of Maths dealing with collection, organisation, analysis, interpretation and presentation of data Sampling frame - correct answer-A list of individuals from whom the sample is drawn that make up a sampling frame Sampling Unit - correct answer-The individual items constituting a population being sampled What affects the size of a sample? - correct answer-The size of the sample depends on the required accuracy, available resources and if the population is very varied, a larger sample will be needed than if it was unified How does the size of a sample affect the conclusions? - correct answer-A larger sample will generally be more accurate and different samples can lead to different conclusions due to natural variation in the population What are the methods of sampling? - correct answer-Simple random sampling, systematic sampling and stratified sampling What is simple random sampling? - correct answer-Every member of the population has an equal probability of being selected for the sample How do you carry out simple random sampling? - correct answer-Simple random sampling is achieved by randomly selecting elements from the sampling frame. Through using a random number generator or lottery sampling (names out of a hat) Advantages of simple random sampling - correct answer-Free of bias + Easy and cheap to implement for small populations and small samples + Each sampling unit has a known and equal chance of selection Disadvantages of simple random sampling - correct answer-Not suitable when the population size or the sample size is large + A sampling frame is needed What is systematic sampling? - correct answer-The required ele