MATH 1040 - Introduction to Statistics

3.1 Observational Studies - Solution for Practice 1

Which stop sign is run through most often? You look at three different stop signs and count the number of cars that pass the stop sign, calculating the percentage of responses in support or against.

Potential Problems to Stop Sign observational study

The stop sign study could be influenced by the location of the stop signs.

It could also be influenced by the intensity of traffic in the area by the stop sign (both car and pedestrian traffic).

Also, the time of day might have an affect on the traffic and the number of run stop signs.

Potential Solutions to Stop Sign observational study

Collect information on the following variables:

• Number of cars that pass through in an hour
• Number of those cars that ran through the stop sign
• Time of day (Morning, Noon, Afternoon, Evening)
• Pedestrian traffic (None, Light, Moderate, Heavy)
• Stop sign location (country, small neighborhood, populated neighborhood, light city, heavy city)

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