Answer Happy

A researcher knows that in spite of the yellow flashing lights
and signs announcing “school zone, 20 mph”, drivers in front of
Elementary School B proceed at a mean speed of 22 mph. The head of
the Police Department’s Traffic Control Division hypothesizes that
having an adult wearing a florescent orange & green vest at the
crosswalks in front of School B will decrease the traffic speed
from the current mean of 22 mph during critical times. Thus, the
comparison mean is = 22 mph. A sample of n = 10 vehicles driving in
front of School B is drawn when the orange lights are flashing AND
an adult in florescent clothing is at the crosswalk. The Traffic
Division’s head finds the following traffic speeds:
The speeds (mph) for this sample of ten cars were: 18, 25, 22,
17, 19, 23, 25, 19, 24, 17
With = .05, determine
the critical value of z* , t*, or r* that needs to be employed
here. The value is:
707
1.833
1.96
2.228
2.292
the correct value of z* , t*, or r* is not listed in
alternatives "a" through "e"