Data Analysis & Reporting Flashcards

A county has 12 burglaries in a population of 60,000. What is the burglary rate per 100,000 residents?

Answer: 20

12 / 60,000 x 100,000 = 20 burglaries per 100,000 residents.

Which measure of central tendency is least affected by one extreme outlier, such as a single call that took 14 hours?

Answer: Median

The median depends on the middle value, so extreme values barely move it.

The clearance rate is calculated as:

Answer: Offenses cleared divided by offenses reported

Clearance rate compares offenses cleared by arrest or exceptional means to offenses known to police.

Which data set is best for identifying the times of day when thefts from vehicles peak?

Answer: Time-stamped incident records

Time-stamped incident data lets analysts group offenses by hour and day.

A bar chart is most appropriate for showing:

Answer: Comparison of offense counts across categories

Bar charts compare discrete categories such as offense types.

A report states that patrol hours increased and burglaries fell, so patrol caused the drop. What is the main flaw?

Answer: Confusing correlation with causation

Two trends moving together does not prove one caused the other without controlling for other factors.

Which statement about writing the narrative of an official incident report is correct?

Answer: Stick to facts, observations, and statements in objective language

Reports should be factual, objective, and complete since they may be used in court.