Descriptive Stats - Part 1
Data that has not been summarised or organised.
What is grouped data?
Data that has been organised into intervals with frequencies.
Why is data grouped?
To simplify large data sets and make patterns easier to analyse.
What is meant by “central tendency”?
A measure that represents the centre or typical value of a data set.
What are the three measures of central tendency?
Mean, median, and mode.
What is the arithmetic mean?
The average of a set of values, calculated by dividing the total by the number of values.
What symbol is used for the mean?
x̄ (x-bar)
How do you calculate the mean?
Mean = (sum of all values) ÷ (number of values)
What does the mean represent?
The central or balancing point of the data.
What is the median?
The middle value in an ordered data set.
What does the median divide the data into?
Two equal halves (50% above and 50% below).
What must you do before finding the median?
Arrange the data in ascending or descending order.
How do you find the median if there is an even number of values?
Take the average of the two middle values.
What is the mode?
he most frequently occurring value in a data set.
Can a data set have more than one mode?
Yes (bimodal or multimodal).
Can a data set have no mode?
Yes, if no value repeats.
Can the mode be used for non-numeric data?
Yes, it can be used for categorical data.
Which measure of central tendency is best for categorical data?
Mode.
Which measure is most affected by extreme values (outliers)?
Mean.
Which measure is best when data contains outliers?
Median.
What is a frequency distribution?
A table showing how often values occur in intervals.
What does “f” represent in grouped data?
Frequency (number of observations in an interval).
What does “m” represent in grouped data?
Midpoint of an interval.
What does “fm” represent?
Frequency multiplied by midpoint.
