Data Analysis and Interpretation Flashcards

A crime analyst calculates the interquartile range (IQR) of response times as 4 minutes. What does the IQR represent?

Answer: The range of the middle 50% of the data

The IQR is the difference between Q3 and Q1, capturing the spread of the middle 50% of data values.

A dashboard shows that 5 out of 8 precincts exceeded their average call volume last month. What percentage of precincts exceeded average call volume?

Answer: 62.5%

5/8 = 0.625 = 62.5% of precincts exceeded average call volume.

An officer reads a report stating that violent crime increased by 150% over a decade. If the base count was 200, what is the new count?

Answer: 500

A 150% increase means adding 150% of 200 (= 300) to the original 200, giving 500.

A table presents arrest data by age group: Under 18=50, 18-25=120, 26-35=90, 36+=40. Which age group accounts for exactly 40% of total arrests?

Answer: 18-25

Total = 300; 18-25 group = 120/300 × 100 = 40% of all arrests.

A crime frequency histogram is right-skewed. What does this tell an analyst about the distribution?

Answer: Most locations have low crime counts with a few high-crime outliers

A right-skewed distribution means most data clusters at lower values, with a tail of a few high values pulling the mean upward.

An analyst compares two precincts over 6 months. Precinct X averaged 42 incidents/month with SD=3; Precinct Y averaged 42 incidents/month with SD=9. Which precinct has more consistent crime numbers?

Answer: Precinct X, because lower SD means less variability

A lower standard deviation indicates less variability around the mean, meaning Precinct X's crime counts are more consistent.

A supervisor wants to compare crime rates fairly between precincts of different population sizes. Which metric should be used?

Answer: Crime rate per 1,000 residents

A crime rate normalized per 1,000 residents allows fair comparison between precincts regardless of population size.