Exploratory Data Analysis & Visualisation — Quiz

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Question 1
What is the main purpose of Exploratory Data Analysis?
A To train the final model
B To understand a dataset's shape, patterns and problems before modelling
C To deploy a dashboard
D To delete all outliers
Question 2
A column has a skew of +1.5. What does that indicate?
A A symmetric distribution
B A long right tail (a few large values)
C Missing data
D A perfect correlation
Question 3
Which Matplotlib pattern is recommended for clear, scalable charts?
A plt.plot() only
B fig, ax = plt.subplots() then draw on ax
C Editing the image afterwards
D Avoiding labels for speed
Question 4
In a boxplot, what does the line inside the box represent?
A The mean
B The median
C The maximum
D The standard deviation
Question 5
What does sns.histplot(..., kde=True) add?
A A scatter plot
B A smooth density curve over the histogram
C A correlation value
D Error bars
Question 6
A correlation coefficient of 0.68 between bill and tip means…
A Bill causes higher tips
B They have a moderately strong positive association
C They are unrelated
D Tips cause bigger bills
Question 7
By the IQR rule, a value is an outlier if it is…
A above the mean
B below Q1 − 1.5×IQR or above Q3 + 1.5×IQR
C any value above zero
D equal to the median
Question 8
Why apply a log transform to a right-skewed column?
A To delete outliers
B To pull in the long tail and make the distribution more symmetric
C To increase the mean
D To change the data type
Question 9
What is the main advantage of Plotly over Matplotlib?
A It is the only one with colour
B It produces interactive charts (hover, zoom)
C It needs no data
D It cannot be exported
Question 10
Which chart best shows how a value changes over time?
A Pie chart
B Line chart
C Heatmap
D Boxplot
Question 11
Why should bar-chart value axes generally start at zero?
A It looks nicer
B A truncated axis exaggerates differences and misleads
C It is required by Matplotlib
D To save space
Question 12
What is the single best habit when you find an outlier?
A Delete it immediately
B Investigate whether it is real or an error, and document your decision
C Ignore it
D Replace it with the mean automatically