Unit 1 Flashcards
Pass Unit 1 exam with 100% (24 cards)
What are the measures of spread?
Which ones are resistant?
Range, IQR, Standard Deviation
The range is not resistant.
Standard Deviation is not resistant
IQR is the resistant measure of spread
What are the measures of center?
Which ones are resistant?
Mean and Median
Median IS resistant to outliers
Mean IS NOT resistant to outliers
What effect does added data have on standard deviation?
If you add a variable to a data set THAT IS CLOSE TO the mean = the standard deviation will decrease
If you add a variable to a data set THAT IS NEAR the mean = the Standard deviation will stay the same
If you add a variable to a data set that is FAR FROM the mean = the standard deviation will increase
What are individuals?
What are variables?
Individuals: the objects described by a set of data
Variable: any characteristics of an individual
What are the 2 types of variables?
Quantitative and Categorical
What are quantitative variables?
What are categorical variables?
Quantitative Variables: take the numerical values for which AVERAGING MAKES SENSE; gives a MEASUREMENT and comes with UNITS
Categorical: places an individual into one of several GROUPS or CATEGORIES
How do you find mean?
How do you find the median?
Mean: add the total amount of values, and then divide by the number of values listed
Median: order the data by least to greatest –> find the number in the middle
- If there are two numbers in the middle, add them, then divide the sum by 2
What does IQR tell you?
How do you find IQR?
IQR is a measure of spread. It tells you the spread of the middle half of your distribution.
(Q3 - Q1)
What does Range tell you?
How do you find range?
The range is a measure of spread. It tells you the spread of your data from the lowest to the greatest value in the distribution
(Max - Min)
How do you determine outliers in the lower quartile?
How do you determine outliers in the higher quartile?
Lower Quartile: [Q1 - 1.5 (IQR)]
Higher Quartile: [Q3 + 1.5 (IQR)]
Describe a distribution that is skewed left
The mean is less than the median
Most of it’s data points are to the right of the graph/distribution
Describe a distribution that is skewed right
The mean is greater than the median
Describe a roughly symmetric and unimodal distribution
The mean and median are equal
The graph is bell shaped
When describing the center of a skewed distribution or one with outliers, use the ___-
Median- median is resistant to outliers
When describing the center of a rough symmetrical distribution or one without outliers, use ____
mean- mean is not resistant to outliers
When describing the outliers of a distribution, use the ____
IQR method to describe the outliers- IQR is resistant to outliers
When is a value an outlier
when it is greater than or equal to [Q3+1.5(IQR)]
and less than or equal to [Q1 - 1.5 (IQ
what is the equation for IQR?
Q3-Q1
what are the steps to finding outliers?
1) Find median
2) Find Q3 and Q1
3) Find IQR
4) Find lower quartile [Q1- 1.5(IQR)]
- Find higher quartile [Q3+1.5(IQR)]
5) Determine: acceptable ranges are greater than Q3 and less than Q1
What does S.O.C.S represent
When do we use S.O.C.S
S) Shape
O) outliers
C) Center
S) spread
+ Context
We use S.O.C.S when describing the DISTRIBUTION of a QUANTITATIVE variable
State sentence frame for describing the distribution of a quantitative variable
The distribution of ( CONTEXT ) is (SHAPE). The distribution is (CENTER), and the (RANGE) varies between (VALUE OF RANGE ). There (ARE/AREN’T) apparent (OUTLIERS)
Which graphs are suitable for quantitative data
Histograms, box plots, stem-leaf plots, bar plots
Which graphs have large standard deviation
Which graphs have smaller standard deviation
Graphs with large standard deviations have a more spread out graph (fat)
Graphs which small standard deviation have a more compressed graph (skinny)
What is standard deviation
The standard deviation is the typical distance from the mean
The (context) typically varies by (standard deviation) from the (mean)
