A Traffic Engineer Plans to Estimate the Average Number of Cars

question 109

Multiple Choice

A traffic engineer plans to estimate the average number of cars that pass through an intersection each day. Based on previous studies the standard deviation is believed to be 52 cars. She wants to estimate the mean to within ±10 cars with 90 percent confidence. The needed sample size for n is:

• A) n = 104 days.
• B) n = 74 days.
• C) n = 10 days.
• D) n = 9 days.

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Definitions:

Microorganisms

Tiny living organisms, such as bacteria, viruses, fungi, and protozoa, that can only be seen under a microscope.

Contaminated

Something that has been made impure or unsuitable by contact or mixture with an unclean or harmful substance.

Plaque Formation

The accumulation of substances on the inner lining of arterial walls, which can lead to arterial blockages and cardiovascular diseases.

Whole Grain Breads

Breads made from flour that contains the entire grain kernel, offering higher nutritional value including fiber, vitamins, and minerals.