Purdue STAT 301 Exam 1 ACTUAL UPDATED QUESTIONS AND CORRECT ANSWERS
Terms in this set (75)
Categorical variable a variable that is described in WORDS (ex: eye color)
Quantitative variable a variable that is described in NUMBERS (ex: weight)
Bar graphs are used for categorical data
Pie charts are used for quantitative data
Stemplots are tables in which NUMERICAL (quantitative) data values are divided into "stems"
that can have multiple "leaves"
Histograms are graphs consisting of vertical bars that touch each other and represent the
frequency distribution of a set of data (quantitative)
bar graph
pie chart
Stemplot
Histogram
Outliers extreme values that don't appear to belong with the rest of the data
influential observation an observation that has a strong influence or effect on the regression results
1 peak= unimodal
2 peaks= bimodal
more than 2 peaks= multimodal
, symmetric mean is equal to median
right skewed mean is greater than median
left skewed mean is less than median
Center of Distribution Described by the mean, median, or mode, it is in some way the middle of the
distribution.
Spread of Distribution Described by Range, Interquartile Range, or Standard Deviation, the spread says
how "wide" the distribution is.
Outliers Any point that falls outside the pattern of the association should be considered an
outlier.
Influential Points A point is influential if it has a big effect on a calculation, such as the correlation or
equation of the least-squares regression line. Points separated in the x-direction
are often influential.
Mean only used when data is NOT skewed, only used with continuous data (ratio or
interval)
Median used when data IS SKEWED, aka 50% percentile, normal distribution curve, can be
used with all the data types
range the difference between the highest and lowest scores in a distribution
IQR (interquartile range) measure of statistical dispersion, being equal to the difference between the upper
and lower quartiles (IQR = Q3 − Q1)
Variance a difference between what is expected and what actually occurs (standard
deviation squared)
standard deviation a computed measure of how much scores vary around the mean score (square
root of variance)
resistant measure A statistic that is not affected very much by extreme observations.
Terms in this set (75)
Categorical variable a variable that is described in WORDS (ex: eye color)
Quantitative variable a variable that is described in NUMBERS (ex: weight)
Bar graphs are used for categorical data
Pie charts are used for quantitative data
Stemplots are tables in which NUMERICAL (quantitative) data values are divided into "stems"
that can have multiple "leaves"
Histograms are graphs consisting of vertical bars that touch each other and represent the
frequency distribution of a set of data (quantitative)
bar graph
pie chart
Stemplot
Histogram
Outliers extreme values that don't appear to belong with the rest of the data
influential observation an observation that has a strong influence or effect on the regression results
1 peak= unimodal
2 peaks= bimodal
more than 2 peaks= multimodal
, symmetric mean is equal to median
right skewed mean is greater than median
left skewed mean is less than median
Center of Distribution Described by the mean, median, or mode, it is in some way the middle of the
distribution.
Spread of Distribution Described by Range, Interquartile Range, or Standard Deviation, the spread says
how "wide" the distribution is.
Outliers Any point that falls outside the pattern of the association should be considered an
outlier.
Influential Points A point is influential if it has a big effect on a calculation, such as the correlation or
equation of the least-squares regression line. Points separated in the x-direction
are often influential.
Mean only used when data is NOT skewed, only used with continuous data (ratio or
interval)
Median used when data IS SKEWED, aka 50% percentile, normal distribution curve, can be
used with all the data types
range the difference between the highest and lowest scores in a distribution
IQR (interquartile range) measure of statistical dispersion, being equal to the difference between the upper
and lower quartiles (IQR = Q3 − Q1)
Variance a difference between what is expected and what actually occurs (standard
deviation squared)
standard deviation a computed measure of how much scores vary around the mean score (square
root of variance)
resistant measure A statistic that is not affected very much by extreme observations.
