paper 1 Flashcards
Equation to find an outlier?
below Q1 - 1.5 x IQR, above Q3 + 1.5 x IQR
what is qualitative data?
cannot be counted, non-numerical
what is quantitative data?
can be counted, usually a number
what is raw data?
data that has not been organised or processed
what is primary data?
data collected for the first time
what is secondary data?
data that has ben collected before, already existed
what is discrete data?
limited number of countable data e.g., people in a class
what is continuous data?
measured on a scale and can take any value on that scale. e.g., height, weight
what is random sampling?
assign a random number to each item, then randomly pick a number to create a sample.
advantages of random sampling
genuinely random so free from bias
disadvantages of random sampling
time consuming, needs a sampling frame, costly
what is stratified sampling?
the population is divided into groups by categories, then a random sample is collected from each category, the size of each sample is proportional to the size of the category
advantages of stratified sampling
more accurate than random, can show different tendencies for each group.
disadvantages of stratified sampling?
time consuming, costly, needs a sampling frame, detailed planning needed
what is cluster sampling?
the population is divided into groups, a random sample of clusters and every item in the cluster is sampled, the smaller the cluster the less likely the sample is biased.
