Flashcards in Describing Data with Numbers Deck (57)
What are quartiles?
Quartiles are what is achieved by dividing the data into 4 equal parts in terms of the number of observations.
What units do you use for standard deviation?
The same units as the data is represented as
What is the formula used to calculate the coefficient of variation?
CV = (s/x̄)*100
What is Q3?
The middle of the top half of results.
What are three statistical tools?
Measures of centre
Measures of dispersion
What does the five-number summary consist of?
When using the coefficient of variation, what is the variability relative to?
The typical value.
What is Σx?
The sum of all numbers.
What type of data are bar graphs associated with?
What is Exploratory Data Analysis?
The process of using statistical tools to investigate data sets in order to understand their important characteristics
What are the two main measures of centrality?
What are outliers?
Sample values that lie far away from the vast majority of other sample values.
What does the standard deviation measure?
The average deviation of observations from the mean.
What is the most common weakness with calculating a range?
Ranges fail to capture the main features of a data set. It only focuses on the extremes.
What is the calculation for the position of the median when the number (n) of observations is even?
Median = average of the n/2th and ((n/2)+1)th observations
What is a less-commonly considered weakness of calculating the range as a degree of spread?
Two completely different data sets can have the same range.
For what types of data sets would you use the mean?
Symmetric distributions without outliers.
What two things is the coefficient of variation used to do?
Measure changes in a population over time
Compare variability of two populations with different units
What is the calculation for the position of the median when the number (n) of observations is odd?
Median = value of the (n+1)/2th observation
What is the relationship between the mean and median for symmetric data sets?
What is the relationship between the mean and median for data sets which are skewed right?
How is the five-number summary represented?
Graphically with a boxplot.
What measure of variability is used with the median?
What is Q1?
The middle of the bottom half of results
What are the three measures of centre?
What is the formula for calculating mean?
When would a bell curve appear rectangular?
When all values occur equally as frequently as one another.
What is the mean?
The arithmetic average value
What is n?
The number of observations