STAT

STAT 375

Homework # 3

Due Feb 7, 2017

[Question 1] Do people walk faster in the airports when they are departing (getting on a plane) or when they are arriving (getting off a plane)? Researchers Seth B. Young measured walking speed of travelers in San Francisco International Airport and Cleveland Hopkins International Airport. His findings are summarized in the table:

Direction of Travels	Departure	Arrival
Mean speed ( feet per minute)	260	269
Standard deviation ( feet per minute)	53	34
Sample size	35	35

Do individuals walk at different speeds depending on whether they are departing or arriving at the = 0.05 level of significance? Use the classical approach to hypothesis testing.

[Question 2]

To test whether ramp metering is effective in reducing travel times, engineers in Minneapolis, Minnesota, conducted an experiment in which a section of the freeway had ramp meters installed on the on-ramps. The response variable for the study was speed of vehicles. A random sample of 15 cars on the highway for Monday at 6 pm with the ramp meters on and a second random sample of 15 cars on a different Monday at 6.00 pm with the meters off resulted in the following speeds (in miles per hour).

Ramp Meters On

28 48 56

38 31 25

43 46 50

35 55 40

42 26 47

Ramp Meters Off

24 26 42

34 37 31

47 38 17

29 23 40

37 52 41

Are the speeds with ramp meter on greater than speeds with ramp meter off at the = 0.10 level of significance? Use the P-value method for hypothesis testing.

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