In a study investigating the effect of car speed on accident severity, 5,000 reports of fatal automobile accidents were examined, and the vehicle speed at impact was recorded for each one. For these 5,000 accidents, the average speed was 43 mph and the standard deviation was 15 mph. A histogram revealed that the vehicle speed at impact distribution was approximately normal.

a. Roughly what proportion of vehicle speeds were between 27 and 57 mph?
b. Roughly what proportion of vehicle speeds exceeded 57 mph?

a) P(27<x<57)=0.68

b) P(X>57)=0.18

Step-by-step explanation:

We have a sample of n=5000 accidents, where the sample mean is 43 mph and the sample standard deviation is 15 mph, with a distribution shape approximately normal.

a) We have to calculate what proportion of vehicle speeds were between 27 and 57 mph.

If the distribution is approximately normal, we can calculate a z-score and then the probability.

b) We have to calculate what proportion of vehicle speeds were 57 mph or more.

We use the same z=0.9333 for X=57, so we can calculate the probability as:

option: d is correct

step-by-step explanation:

points are handed out whenever you post answers.

brainliest answers are handed out by the person asking the question, so whether your answer is picked depends entirely on whether the asker bothers to pick

if you're asking about your rank, it depends on having a certain number of points and a certain number of brainliest answers. for example, at the time of this writing, i have 44338 points out of 15000 needed for the next (nearly triple the requirement! ) but i only have 24 out of 50 required brainliest answers. this number decays, meaning after a certain amount of time (i think about a month), the total number of brainliest answers you've earned doesn't count toward this total. (i've been stuck at the same rank for a long

the lesson to learn here is that you shouldn't worry about points or rank. chances are, no matter how good an answer you may provide, your efforts will go mostly unnoticed unless you focus on the newest/most active questions that get posted.