School

Valencia College, Osceola **We aren't endorsed by this school

Course

STA 2023

Subject

Statistics

Date

Aug 28, 2023

Pages

1

Uploaded by Michellelola on coursehero.com

Real
life:
We
only
get
one
chance
In
simulations
we
repeat
the
survey
many
times
to
understand,
but
in
real
life
we
just
get
one
chance.
Bias
and
precision
are
both
measures
of
what
happens
if
we
could
repeat
the
survey
many
times.
Bias
indicates
the
typical
outcome
of
surveys
repeated
again
and
again.
If
the
bias
1s
0,
we
will
usually
get the
right
value.
If
the
bias
is
0.10,
then
our
estimate
will
characteristically
be
10
percentage
points
too
high.
Precision
measure
how
much
our
estimator
will
vary
from
the
typical
value
if
we
do
the
survey
again.
If
someone
else
does
the
survey
how
different
will
that
person's
estimate
be
from
ours.
If
real
life
we
don't
know
the
true
value
of
the
population
proportion,
p.
Which
means
we
can
not
calculate
the
standard
error.
We
can
come
close
if
we
use
the
sample
proportion,
P
.
1.
-©
AneNie
Estimated
standard
error:
est
Book
Problems:
23
(use
the
example
we
did
in
notes),
25,27,31
*7.25
Bias?
Suppose
that,
when
taking
a
random
sample
of
4
from
123
women,
you
get
a
mean
height
of
only
60
inches
(5
feet).
The
procedure
may
have
been
biased.
What
else
could
have
caused
this
small
mean?
7.27
Proportion
of
Odd
Digits
A
large
collection
of
one-digit
random
numbers
should
have
about
50%
odd
and
50%
even
digits
because
five
of
the
ten
digits
are
odd
(1,
3,
5,
7,
and
9)
and
five
are
even
(0,
2,
4,
6,
and
8).
a.
Find
the
proportion
of
odd-numbered
digits
in
the
following
lines
from
a
random
number
table.
Count
carefully.
55185
74834
81172
89281
48134
71185
b.
Does
the
proportion
found
in
part
(a)
represent
p
(the
sample
proportion)
or
p
(the
population
proportion)?
c.
Find
the
error
in
this
estimate,
the
difference
between
p
and
p
(or
p
=
p).
¢«
7.31
What
Is
the
Proportion
of
Seniors?
A
population
of
a.
Use
the
first
line
(reprinted
here)
from
the
random
number
table
to
select
your
sample
of
two.
(The
selections
are
underlined.)
02779
72645
32699
86009
Report
the
percentage
of
seniors
in
the
sample.
(Count
the
number
of
4s
and
5s
and
divide
by
the
sample
size
2.)
b.
Use
the
next
line
to
select
your
sample
of
two.
31867
85872
91430
45554
Report
the
percentage
of
seniors
in
the
sample.
¢.
Use
the
next
line
to
select
your
sample
of
two.
07033
75250
34546
75298
Report
the
percentage
of
seniors
in
the
sample.
d.
Use
the
last
line
to
select
your
sample
of
two.
09084
98948
09541
80623
Report
the
percentage
of
seniors
in
the
sample.
e.
Fill
in
the
rest
of
the
table
below,
showing
the
results
of
the
four
samples:
p
(Population
p
(Sample
Proportion
of
Proportion
Repetition
Senio
i
o
B
college
students
is
taking
an
advanced
math
class.
In
the
class
3
rs)
of
Seniors)
Error:
p
—
p
are
three
juniors
and
two
seniors.
Using
numbers
1,
2,
and
3
to
1
(from
part
a)
2/5=04
1/2=05
05-04=0.1
represent
juniors
and
4
and
5
to
represent
seniors,
sample
wn:.hout
5
replacement.
Draw
a
sample
of
two
people
four
times
(once
in
each
(from
part
b)
3
of
parts
a,
b,
¢,
and
d),
and
then
fill
in
the
following
table.
4

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