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51 Cards in this Set
- Front
- Back
numbers and/or category labels that have been collected (measured) but have not yet been processed in any way
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raw data
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the entire group of objects or individuals under study, about which information is wanted
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population
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an individual object or person in the population
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unit
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The units are often called this if the population consists of people
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subjects
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a part of the population that is actually used to get information
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sample
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a characteristic of interest to be measured for each unit in the sample
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variable
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A collection of observations on one or more variables is called a?
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data set
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raw data that consists of group or category names
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qualitative variables
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If the category names do not necessarily have a logical ordering
Examples: eye color, country of residence. |
nominal variables
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If the category names do have a logical ordering
Examples: highest educational degree earned, shirt size (S, M, L, XL) |
ordinal variables
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raw data that consists of numerical values taken on each individual, have numerical values that are measurements (length, weight, and so on) or counts (of how many)
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quantitative variables
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variable is one for which you can count the number of possible values
Example: the number of correct answers on a multiple-choice test |
discrete
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variable can take on any value within a given interval.
Example: the amount of water poured into a 50-ml glass container. |
continuous
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In general, the value of the ___________ variable for an individual is thought to partially explain the value of the ________ variable for that individual.
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explanatory; response
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provides the possible values that a variable can take on and how often these possible values occur
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distribution
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displays the distribution of a qualitative variable by dividing a circle into wedges corresponding to
the percentage of items in that category |
pie chart
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displays the distribution of a qualitative variable by listing the categories of the variable along one
axis and drawing a bar over each category with a height (or length) equal to the percentage of items in that category |
bar graph
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Two types of Qualitative Variables?
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1. Nominal
2. Ordinal |
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Two Types of Quantitative Variables?
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1. Discrete
2. Continuous |
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How many equally spaced intervals are good for a histogram?
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between 6 to 15
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count
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frequencies
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proportion
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relative frequencies
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displays a dot for each observation along a number line
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dotplot
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contains all but the last of the displayed digits of a number
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stem
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the last of the displayed digits of a number
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leaf
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Two things to look for in any graph of data?
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Overall pattern and for striking deviations from that pattern
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Three things that describe the overall pattern?
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Shape, center, and spread
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an individual value that falls outside the overall pattern
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outlier
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if the right and left sides of the histogram are approximately mirror images of each other
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symmetric
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if the right side of the histogram (containing the half of the observations with the larger values) extends much farther out than the left side
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skewed to the right
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if the left side of the histogram extends much farther out than the right side
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skewed to the left
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Normal shape of distribution?
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Symmetric, bell-shaped, unimodal
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plots each observation against the time at which it was measured
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time plot
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What does a time plot help determine?
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Whether a distribution is changing over time
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average value in a data set
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mean
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midpoint of a distribution
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median
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Because the mean cannot resist the influence of extreme observations, we say that it is?
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not a resistant measure of center
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The median is this to extreme observations?
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resistant
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The mean and median of a symmetric distribution are?
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exactly the same
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The simplest useful numerical description of a distribution consists of?
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both a measure of center and a measure of spread
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high value - low value
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range
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upper quartile - lower quartile
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interquartile range (IQR)
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median of data values that are below the median
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lower quartile
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median of data values that are above the median
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upper quartile
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the median of the observations whose position in the ordered list is to the left of the location of the overall median
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lower quartile Q1
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the median of the observations whose position in the ordered list is to the right of the location of the overall median
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upper quartile Q3
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consists of the smallest observation, the first quartile, the median, the third quartile, and the largest observation, written in order from smallest to largest
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five-number summary
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a number that has k% of the data values at or below it and (100-k)% of the data values at or above it
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k^th percentile
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In a dataplot, points represented by asterisks are considered to be?
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outliers
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Q3 - Q1
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interquartile range
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Are fences sketched on a boxplot?
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No
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