Posted by **kate** on Thursday, August 23, 2007 at 1:18am.

A police officer gathered data on the speeds, in kilometres per hour (km/h), of some cars as they drove down hill towards her car. The speed limit is 50 km/h. Analysis of the results showed that the speeds of the cars were normally distributed with a mean speed of 56 km/h and a statndard deviation of 8 km/h.

" slow drivers" contribute to road rage problems and the officer noticed that 2 of the 150 drivers in her survey caused problems for other drivers beacuse of their slow speed. Use normal distrubution and this infomation to decribe a "slow" driver in terms of their driving.

thanks

- Maths -
**economyst**, Thursday, August 23, 2007 at 10:04am
I think I see what you are after here; I think you are trying to find the speed definition of "slow"

2 out of 150 is .0133. That is 1.33% of drivers are slow. Ergo, 1-.0133=.9866 are not slow. Look up .9866 in a normal distribution table (probably found in your stats book). I get 2.22. Meaning that 1.33% of the population are more than 2.22 standard deviations away from the mean (of a normally distributed population). So 8*2.22 = 17.76. And 56-17.76 = 38.24. Meaning, drivers going below 38.24 km/h are "slow drivers".

By the way, in my opinion, 150 drivers is too small of a sample size to determine the number of "slow" drivers. But this is an issue for another day.

## Answer This Question

## Related Questions

- maths - the police officer also gathered data on the speedsx, in kilometers per ...
- Physics - A speeding motorcyclist is traveling at a constant speed of 31.1 m/s ...
- MCC - There are two race cars. the sum of their fastest speed is 50o.3 miles per...
- PHYSICS-URGENT HELP - A stationary police car emits a sound of frequency 1200 Hz...
- physics - You are arguing over a cell phone while trailing an unmarked police ...
- statistics - Hello i am doing assignment in my math 20-2 class. The question is...
- math - Mary and John are 128 miles apart. A car leaves Mary traveling towards ...
- Math - Hello i am doing assignment in my math 20-2 class. The question is: data ...
- Calculus - The police department must determine a safe speed limit on a bridge ...
- mitx 8.01x Classical Mechanics - A motorist traveling with constant speed of vc...

More Related Questions