1. UNIT ONE REVIEW
Exploring Data

2. Vocabulary
Data Analysis – organizing, displaying, summarizing, and asking questions about data
Individuals – people, animals, or things described by a set of data
Variable – characteristics of an individual
Categorical – placed into groups
Quantitative – numerical value
Distribution – shows values the variable takes and how often it takes these values
Inference – drawing conclusions that go beyond the data at hand
Roundoff Error – data doesn’t add up to 100%; effect of rounding off results
Marginal Distributions – of one of the categorical variables in a two-way table of counts is the distribution of values of that variable among all individuals described by the table.
Conditional Distribution – of a variable describes the values of that variable among individuals who have a specific value of another variable.
Association – occurs when knowing the value of one variable helps predict the value of the other.

3. Vocabulary Frequency Table – displays actual counts in each category
Relative Frequency Table – shows percentages of each category
Two-way Table – describes results to the same question of two categorical variables
Pie Chart –
Bar Graph –
Segmented Bar Graph –

4. Vocabulary
Dotplot –
Overall Pattern – described by shape, center, and spread
Departures – data that strays from the overall pattern
Shape – symmetry, uniformity, skewedness
Center – mean or median
Spread – range
Outlier – a departure that falls outside of the overall pattern
Symmetry – graphs where left and right sides are nearly mirror images of each other
Skewness – describes shape by looking at “tails”
To the Left: left side of graph is longer
To the Right: right side of graph is longer
Modes – describes shape by looking at peaks
Unimodal
Bimodal
Multimodal

5. VOCABULARY
Stemplot – give us a quick picture of the shape of a distribution while including the actual numerical values in the graph
Stem
Leaf
Splitting Stems – stemplot where each stem is broken in half to more clearly see the data
Back-to-Back Stemplot – compares categories of data on a stemplot

6. VOCABULARY Histogram –
Range – measures spread; largest data point minus the smallest data point.
First Quartile – median of the observations that are to the left of the median in the ordered list
Third Quartile – median of the observations that are to the right of the median in the ordered list
Interquartile Range (IQR) – IQR=Q3 −Q1
Five Number Summary – Minimum Q1 Median Q3 Maximum
Boxplot – graphs the five number summary
Variance – average squared deviation
Standard Deviation – measures the typical distance of the values in a distribution from the mean
VOCABULARY
Histogram –
Mean (x-bar) – the most common measure of center; ordinary arithmetic average
Resistant Measure of Center – mean is NOT resistant because it cannot resist the influence of extreme observations; median is usually resistant
Median – the midpoint of a distribution; the number such that about half the observations are smaller and about half are larger

7. Four Step Process

8. How do we analyze data? Look at variables individually.
ALWAYS graph your data!!! Pictures are so important.
Dotplot/Stemplot: small sets of data
Histogram: large sets of data
Add numerical summaries.
Look for an association between the variables.
Use the acronym SOCS – Shape, Outliers, Center, Spread – to describe data.
Use comparison words: “greater than” or “approximately the same”
Find the mean or median and the quartiles.
Outliers (>Q3+1.5xIQR or <Q1-1.5xIQR)?