town survey of 890 people, 463 said they
greater police presence. Find
2. In a
wanted to see
a) ê, the sample percent,
b) Sp, the standard deviation,
c) the margin of error, and
d) the
95% confidence interval.
e) Are you 95% confident that more than half
of the population want to see a greater police
3. For each of the scenarios below the data gathered
not reliable. Choose among confounding, convenience,
and voluntary response to
say why not.
is
a) A new stadium, built with tax monies, is being
planned for the local professional football team. To
determine public opinion of this plan, the first
the old stadium for
game
200
people entering
are surveyed.
b) A health food magazine asks its readers who
take large doses of vitamins to write in and describe
benefits.
the
a
c) A school principal, concerned about the increasing
level of absenteeism, called a meeting of parents at
which she described an experimental progam
absenteeism. After two months it was down by 15%.
d) A local cafe invites its clientele to complete
to curb
comment cards.
e) A student at the bus stop on the New Haven
green asks some passengers as they get off
the bus if they are in favor of the U.S. going
into Iran.