Describe and Provide Examples of the Most Important Statistical Measures and Effective Visualizations of Data DATA-SCIENCE-FOUNDATIONS Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A quality control engineer is analyzing the diameter of manufactured bolts. The specification requires a diameter of 10.0 mm. The engineer calculates the mean diameter as 10.0 mm and the standard deviation as 0.5 mm. The engineer also notes that the distribution is bimodal, with peaks at 9.8 mm and 10.2 mm. What is the most important limitation of reporting only the mean and standard deviation in this case?

   • AThe mean and standard deviation do not reveal the bimodal nature of the data, which suggests two distinct production processes or settings.
   • BThe standard deviation should be reported as the range instead.
   • CThe mean is incorrect because it does not equal either of the peaks.
   • DThe standard deviation is too large, indicating the process is out of control.
   Reveal Solution Discussion Select an answer first
2. 2application · easy

   A data analyst is summarizing the number of support tickets closed per day over the past month. The data is roughly symmetric with no outliers. The analyst needs to report a single 'typical' value and a measure of how much daily ticket counts vary. Which pair of statistics is most appropriate?

   • AMean and range
   • BMedian and interquartile range (IQR)
   • CMean and standard deviation
   • DMode and range
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4. 3application · medium

   An analyst is investigating whether there is a relationship between the number of ice cream sales and the number of drowning incidents in a coastal city. The Pearson correlation is r = 0.85. What is the most important caveat to consider before reporting this finding?

   • AThe correlation is strong, so the city should consider limiting ice cream sales to reduce drownings.
   • BThe correlation does not imply causation; a third variable, such as hot weather, likely drives both ice cream sales and swimming activity.
   • CThe correlation is weak, and there is no meaningful relationship.
   • DThe analyst should use a box plot to confirm the relationship.
   Reveal Solution Discussion Select an answer first
5. 4application · medium

   A healthcare analyst is examining the distribution of patient wait times at a clinic. The histogram shows a long tail extending to the right, with the mean (42 minutes) greater than the median (30 minutes). Which conclusion about the distribution's shape is most accurate, and what does this imply for reporting?

   • AThe distribution is symmetric; the mean and median are both equally representative.
   • BThe distribution has high kurtosis; the mean is the best summary because it includes all data points.
   • CThe distribution is negatively skewed; the median is the better summary for most patients.
   • DThe distribution is positively skewed; the median is the better summary for most patients.
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6. 5foundation · easy

   A data scientist wants to visualize the distribution of a continuous variable, such as customer age. Which chart type is most appropriate?

   • AHistogram
   • BBar chart
   • CLine chart
   • DPie chart
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