Question

I need help with - Are there any​ outliers? - thank you!

Ramp metering is a traffic engineering idea that requires cars entering a freeway to stop for a certain period of time before joining the traffic flow. The theory is that ramp metering controls the number of cars on the freeway and the number of cars accessing the​ freeway, resulting in a freer flow of​ cars, which ultimately results in faster travel times. To test whether ramp metering is effective in reducing travel​ times, engineers conducted an experiment in which a section of freeway had ramp meters installed on the​ on-ramps. The response variable for the study was speed of the vehicles. A random sample of 15 cars on the highway for a Monday at 6 p.m. with the ramp meters on and a second random sample of 15 cars on a different Monday at 6 p.m. with the meters off resulted in the following speeds​ (in miles per​ hour).

Ramp_Meters_On   Ramp_Meters_Off
28   23
39   35
42   46
36   29
42   36
47   26
31   36
46   38
56   22
27   52
56   41
24   30
51   17
40   40
48   42

Does there appear to be a difference in the​ speeds?

A.

​Yes, the Meters On data appear to have higher speeds.

B.

​No, the box plots do not show any difference in speeds.

C.

​Yes, the Meters Off data appear to have higher speeds.

Are there any​ outliers?

A.

​No, there does not appear to be any outliers.

B.

​Yes, there appears to be a high outlier in the Meters Off data.

C.

​Yes, there appears to be a high outlier in the Meters On data.

D.

​Yes, there appears to be a low outlier in the Meters On data.

Answer 1

Box and whisker plot given below-

from this,

​No, there does not appear to be any outliers.