Exercises •184-·188: Speed of cars passing a certain milepost on Interstate 90 f
ID: 3048565 • Letter: E
Question
Exercises •184-·188: Speed of cars passing a certain milepost on Interstate 90 follows a normal distribution with a mean of 70 miles an hour and a standard deviation of 4 miles an hour. Use this information to find the probability that:
184. the next car is driving more than 74 miles an hour.
185. the next car is driving less than 62 miles an hour.
186. the next car is driving more 'than 78 miles an hour.
For any normally distributed population, find the probability that a randomly chosen outcome will fall:
187. between the mean and 1.2 standard deviations above the mean.
188. More than 2.2 standard deviations below the mean.
189. Between z=-1.4 and z=.45
Explanation / Answer
184)
probability the next car is driving more than 74 miles an hour
185)
186)
187) P(0<Z<1.2) =0.8849-0.5 =0.3849
188)P(Z>2.2 )=1-P(Z<2.2)=1-0.9861 =0.0139
189)+P(-1.4<Z<0.45)=0.6736-0.0807 =0.5929
for normal distribution z score =(X-)/ here mean= = 70.000 std deviation == 4.0000Related Questions
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