Sample Examination One - La Jolla High School

18 Sample Examination One Section I
35. At a cedain high school a simple random sample u,as taken asking fifty-two 11th and
l2th graders their political afflliation. The follou,ing two-way table rvas established, If
a y2 test of independence were perfomed on these data, what would be the
corresponding degrees of freedom?
rA.I
(B)
(c)
(D)
(E)
i
a
a
J
o
1<
11th Grade 12th Grade
Republican t1 5
Democrat 10 t5
lndependent 5 6
36. A student is interested in the effects of different walking styles on heart rate. He decides
to use 30 volunteers from his school for his experiment. All 30 parlicipants find their
at-rest pulse rates. Each parlicipant will walk twice for l0 minutes, once using a fast
pace but with no arm movement and again using a fast pace, but u,ith an exaggerated
affn movement style. The experimenter throws a coin to determine which style each
participant r.l'ill r.valk first. All participants get sufficient rest betrveen rvalks to let their
pulse rates return to normal. The student then compares increased pulse rate based on
the walk with no arm movement to increased pulse rate based on the r,r,alk u,ith
exaggerated arrn movement for each student.
Which of the following statements is true?
Ansrver
(A) This is an observational study, and not an experiment, therefore no conclusion
can be reached regarding u'alking style and pulse rate.
(B) Observations in this study are independent.
(C) Blocking is used in this study to reduce difference in increased pulse rates among
individual students.
(D) Because subjects rvere not assigned randomly to a control or an experimental
group, the design of the experiment was flawed.
(E) This is an example of a completely randomized comparative experiment without
blocking.
Unauthorized copying or reusing any
part of this page is illegal.
Answer