Everything Flashcards
What is a census?
A survey of a whole population.
What is a sample?
A smaller number of items from the population.
What does ‘biassed sample’ mean?
Not representative of everyone in the population.
Define discrete data.
Row value, grouped data with no inequalities.
Define continuous data.
Grouped data with inequalities.
What is systematic sampling?
Finding nth interval = Population size / Sample size.
What is stratified sampling?
Members of each stratum are in proportion to the size of the stratum.
What is random sampling?
Every member of the population has an equal chance of being selected.
What is frequency density?
Frequency / Class Width.
What is qualitative data?
Non-numerical observations.
What is primary data?
Collected by, or for, the person using it.
What is secondary data?
Has already been collected by someone else.
What is a control variable?
Variable that is kept constant during an experiment.
What is a matched pairs test?
Two groups of equally matched people used to test the effect of a particular factor.
What is skewness?
A measure of the asymmetry of the probability distribution of a real-valued random variable.
What does PMCC stand for?
Pearson’s Product-Moment Correlation Coefficient.
What does SRCC measure?
The strength of the correlation between two variables.
What is a line of best fit?
A straight line that best represents the data on a scatter plot.
What does interpolation mean?
Using the line of best fit to estimate within the range of values already plotted.
What is extrapolation?
Extending the line of best fit and reading values outside the range of values plotted.
What is cumulative frequency?
A running total of the frequencies of each class interval.
What is the interquartile range (IQR)?
IQR = Upper Quartile (UQ) - Lower Quartile (LQ).
Define standard deviation.
A measure of how far all the values are from the mean value.
What is a random response method?
Uses a random event to decide how to answer a question.
What is the mode?
The most common value in a dataset.
What is the median for discrete data?
(n + 1)th value.
What is the formula for the equation of the line of best fit?
y = ax + b.
What is the definition of a population in statistics?
Everything or everybody that could possibly be involved in an investigation.
What are outliers?
Values that lie outside the normal range of data.
What is a scatter diagram used for?
To display bivariate data.
What is a qualitative question?
A question that has no suggested answer.
What is a closed question?
A question with a set of given answers to choose from.
What is the purpose of using simulations in data collection?
To model random real-life events and predict outcomes.
What is the formula for the Petersen capture-recapture method?
N = (Mn) / m.
What is the ‘response variable’ in an experiment?
The variable that is measured to see how it is affected.
What is the difference between qualitative and quantitative data?
Qualitative data is non-numerical; quantitative data is numerical.
What is the weighted mean?
Mean calculated for data with different weights for each group.
What is the geometric mean?
The nth root of the product of n values.
What does ‘cumulative frequency curves’ represent?
Used for continuous data to show running totals.
What is the purpose of a sampling frame?
A list of people/items that are to be sampled.
What is a cluster sampling method?
The population is divided into groups, and then groups are randomly selected.
What is systematic sampling?
Choosing a starting point at random and then selecting every nth member.
