Exploring One–Variable Data
When comparing distributions using back-to-back stem-and-leaf plots for two related variables, what potential issue should be carefully considered?
Equal counts across stems may indicate uniformity that could mislead comparisons by suggesting similar distributions when differences exist.
Disparity in leaf unit sizes between plots might cause confusion regarding relative magnitudes within and across variables being compared.
Overlapping stems might create an illusion of similar variability even if other aspects of distributions differ significantly.
Skewedness in one or both distributions could make direct comparison difficult as it suggests non-similarity between groups.
What aspect of comparing back-to-back stem-and-leaf plots can reveal significant differences in distribution shapes between two related groups when numerical summaries appear similar?
Identical stems that confirm similarity in central location measurements.
Equal count of leaves across corresponding stems suggesting same variability.
Symmetric leaf arrangement reinforcing comparability of group distributions.
Variations in leaf spread on either side indicating skewness disparities.
Which graph is created by dividing the range of the quantitative data into equal-width intervals and representing the number or proportion of observations that fall within each interval with the height of bars?
Dotplot
Bar graph
Histogram
Stem-and-leaf plot
When constructing a box plot of a dataset, what subtle feature would suggest the presence of potential outliers if the interquartile range is relatively small?
The median is closer to one end of the box than the other.
The whiskers are disproportionately long compared to the box.
The size of the box is nearly identical to the length of one whisker.
There's an unusually large gap between consecutive data points within the box.
What is the most appropriate measure of center for a skewed distribution?
Range
Median
Mean
Mode
If data analysis shows that students who participate in sports have higher GPAs, what should be concluded about this association?
Sports participation is unrelated to student's academic performance as measured by GPA.
Students with high GPAs are more likely to engage in sports than those with lower GPAs.
There may be an association between sports participation and GPA, but this doesn't mean participation causes higher GPAs.
Participation in sports leads directly to higher GPAs for students.
When comparing the distributions of two different classes' test scores, which graphical representation would allow you to see both the center and spread for each class's scores on the same graph?
Single boxplot
Back-to-back stemplot
Histogram with non-overlapping intervals
Pie chart with percentages

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What conclusion might one draw regarding possible economic trends when histograms of household incomes over several years begin to show increasingly bi-modal distributions?
Increasingly bi-modal distributions merely point out that more people are moving into middle-income brackets, signifying a positive development in the economy without further issues needing resolution.
Bi-modal distributions point towards an emerging divide in economic status with distinct groups reflecting different income levels. This indicates widening inequalities and has implications for economic policy or intervention.
These trends reflect normal fluctuations with no real connection to broader socioeconomic conditions or policymakers should not read into them too much, thereby maintaining the status quo approach.
No significant implications can be determined from changes in shape of distribution as it is likely due to random variance rather than any actual shift in economic situation.
Which of the following is an example of a continuous variable?
Number of cars on a highway
Number of apples eaten
Time spent sleeping
Number of books read
In examining residual plots for linearity assumption verification after linear regression analysis, what pattern would indicate potential violation?
Consistent distances between adjacent residual points suggest equal error variance but do not address whether there is a linear relationship present amongst variables analyzed via regression models.
A clear curve-like pattern within residuals suggests non-linearity between independent and dependent variables violating assumptions of linear regression model fitting.
Clusters of residuals at certain values indicate possible influential points but do not inherently violate linearity unless showing systematic curvature patterns.
Randomly scattered points generally centered around zero imply proper fit without systematic patterns indicating good adherence to linearity assumptions.