Keywords Flashcards
Arithmetic Mean
the correct name for the mean as it is usually worked out
Average
the general name given to the measures of central location (mode, median and mean) : a typical value from data
Base Year
the year which is the starting point from which all other years are compared, with the base year being given the value 100
Bias
the name given to a sample that does not fairly represent the population it comes from
Bimodal
a set of data that has two modes
Bivariate Data
data that has two variable as in a scatter diagram
Census
the data is obtained from every member of the population
Chloropeth Map
a diagram where different shades or colours represent the data
Continuous Data
data that can take any value between set limits
Correlation
the measure of agreement between two variables
Deciles
where ordered data is split into ten equal groups
Discrete Data
data that can only take specific values
Dispersion
the spread or width of data
Event
in probability something which takes place such as rolling a die etc.
Explanatory Variable
the variable you control, whose effect you want to investigate
Extrapolation
an estimate made using a line of best fit from outside the range of data given
Frequency Density
used to draw a histogram and is the actual frequency divided by the class width
Frequency Polygon
a diagram for continuous data joining the midpoints of the class intervals at the appropriate frequencies
Hypothesis
a statement you make which you think might be true
Independent
two events are independent if the outcome of the second is not affected by the outcome of the first
Index number
(current value of item/value of item in base year) x100
Interpolation
a value found from a line of best fit from within known data values
Interquartile Range
the upper quartile minus the lower quartile
Lower Quartile
the value one quarter of the way up the data (often written as Q1)
Moving Average
the mean of one cycle of data in a time series which gives a better view of the overall trend
Mutually Exclusive
events that cannot both occur at the same time
Negative Correlation
when one variable increases as the other decreases
Open Ended Class
a class interval where the upper bound is not defined
Outlier
a value that does not fit in well with the rest of the data
Percentile
where ordered data is split into a hundred equal groups
Pilot Survey
a small scale survey carried out before the main survey
Population
every possible item that could occur in a given situation
Positive Correlation
when one variable increases as the other increases
Primary Data
data you collect yourself
Proportional Pie Chart
the areas of the pie charts are used to compare the frequencies of the data
Qualitative Data
non numerical data such as colour or favourites
Quantitative Data
numerical data
Quota
a specific number of people or items with a specific feature
Random Sample
a sample where each member of the population has an equal chance of being selected
Rank
the position of a piece of data in an ordered list
Relative Frequency
a name for experimental probability
Response Variable
the value that depends on changing the explanatory variable; the outcome you measure
Sample
part of the population from which information is taken
Sample Frame
the list of all members of the population available to be sampled
Seasonal Effects
variation in data that follows a regular time pattern
Secondary Data
data that someone else has collected
Skew Data
data that is unequally spread either side of a central value
Spread
whether values in a set of data are close to each other
Stratified Sample
a sample with consideration for different groups within the population
Symmetrical Data
data that i s equally spread either side of the centre
Time Series
any set of data that has values recorded at different times
Upper Quartile
the value three quarters of the way up the data (often written as Q3
