Descriptive Statistics / Graphs Flashcards
What are descriptive statistics?
The use of graphs, tables and summary statistics to identify trends in a data set.
What are measures of central tendency?
A descriptive statistic that provides information about an ‘average’ value for a data set. (MEAN, MEDIAN, MODE)
What is the mean?
The arithmetic average of a data set that takes all data into account
What is the median?
The middle value of a data set when the items are placed in rank order.
What is the mode?
The most frequently occurring value in a set of data.
What are measures of dispersion?
A descriptive statistic that provides information about how spread out a set of data are.
Outline the 2 measures of dispersion?
Range (difference between highest and lowest item in a data set) and standard deviation (tells us how much scores deviate from the mean.)
1 Strength and 1 limitation of using the mean
Most sensitive measure of central tendency. Takes into account all values.
Easily distorted by extreme values (lead us to misinterpret data as a whole)
What is 1 strength and 1 limitation of using the mode?
More useful for nominal data.
Not always representative of the whole data
What is a limitation of using the range?
Only takes into account the two most extreme values.
What is 1 strength and 1 limitation of using the standard deviation?
A precise measure of dispersion.
Can be distorted by extreme values
What are 5 ways of presenting quantitative data? Discrete, continuous, correlation
- In a table (All)
- Bar charts (Discrete)
- Scattergrams (Correlation)
- Histograms (Continuous)
- Line graphs (continuous)
What is a normal vs skewed distribution?
Normal - A symmetrical spread of frequency data that forms a bell-shaped pattern.
Skewed - A spread of data that is not symmetrical
Where do mean median and mode go on a positive vs negative skew
From left to right on graph:
Positive - Mode, Median, Mean
Negative - Mean, Median, Mode
What is a negative skew?
A type of distribution where the long tail is on the negative side of the peak and most distribution is concentrated on the right. Mean lower than median and mode.
