Averages and Measures of Spread - L3
Studied by 1 person
Learn
Practice Test
Spaced Repetition
Match
Flashcards1/22
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
23 Terms
What are the 3 types of average?
Mean
Median
Mode
How do you calculate the mean?
Add up all of the values and divide the total by the number of subjects
What is the median?
The middle observation in an ordered data set
What is the mode?
The value that appears most frequently
What is normal distribution?
A bell shaped curve where the mean and median are about equal
What is positively skewed distribution?
The mean is greater than the median. The peak of the curve is towards the lower end of the scale
What is negatively skewed distribution?
The median is greater than the mean. The peak of the curve is towards the higher end of the scale
What is a percentile?
A value at or below which a specified percentage of the values in the distribution fall
How do you calculate the value of a percentile?
(Percentile/100) x (number of values + 1)
What percentage is a quintile worth?
20%
What percentage is a decile worth?
10%
What percentage is a tertile worth?
33.3%
What are the 4 measures of spread?
Range
Interquartile range
Standard deviation
Variance
What is the range?
The difference between the highest and lowest values of a data set
What is the interquartile range?
The difference between the upper and lower quartiles
What does standard deviation measure?
The average deviation of the data from the mean
What is variance?
Standard deviation squared
What are box plots?
Graphs of median, interquartile range, and outliers
How do you calculate the lower fence of a box plot?
Lower quartile - (1.5 x interquartile range)
How do you calculate the upper fence of a box plot?
Upper quartile + (1.5 x interquartile range)
Are box plots suitable for ordinal data?
Yes but only if the data set has high enough resolution for a median to be calculated properly
What is the residual?
The difference between a particular observation and the mean of the whole data set
(y - y bar)
How do you calculate standard deviation?
Square root of [(sum of residuals)2 / (n - 1)]