Midterm 2 - Version A

Midterm 2 - Version A - PSYCHOLOGY
60
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Unformatted text preview: PSYCHOLOGY
60
 SPRING,
2010
 
 
 
 
 
 MIDTERM
2
 Tuesday,
May
18th,
2010
 
 
 
 
 
 
 FULL
NAME
___________________________________________________________________________________
 
 
 
 
 
 STUDENT
ID
__________________________________________________________________________________
 
 Please
put
your
name
and
ID
number
on
this
page
AND
on
the
Scantron
form.
 
 
 
 
 
 
 
 
 
 VERSION
A
 
 
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 This
page
is
intentionally
blank.
 
 2
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 3
 
 
 
 1. Phoney
Wireless
is
trying
to
get
into
the
text
messaging
business
and
wants
to
determine
 whether
UCSD
students
send
text
messages
at
a
different
rate
than
the
general
public.

The
 average
number
of
texts
per
day
sent
by
young
adults
in
the
United
States
is
25,
with
σ
=
10.
A
 random
sample
of
25
UCSD
students
finds
that
students
at
UCSD
send
an
average
of
20
texts
per
 day.
What
is
the
appropriate
observed
test
statistic
for
this
study?
 a) tobserved
=

‐2.5
 b) zobserved

=
­2.5
 c) zobserved
=
‐0.5
 d) tobserved
=
‐0.5
 e) zobserved
=
2.5
 
 2. Given
your
test
statistic
in
the
previous
question,
what
should
Phoney
Wireless
conclude
with
α
 =
.05?
 a) Reject
H0
and
conclude
that
UCSD
students
text
less
than
the
average
young
adult
 in
the
US
 b) Accept
H0
and
conclude
that
UCSD
students
text
the
same
as
average
young
adults

 c) Reject
H0
and
conclude
that
UCSD
students
text
the
same
as
average
young
adults
 d) Fail
to
reject
H0
and
conclude
that
it’s
not
worth
it
to
advertise
at
UCSD
 e) Fail
to
reject
H0
and
conclude
that
UCSD
students
text
less
than
the
average
young
adult.
 
 3. What
happens
as
alpha
increases?
 a) The
probability
of
rejecting
H0
increases,
if
H1
is
true
 b) The
probability
of
rejecting
H0
increases,
if
H0
is
true

 c) The
probability
of
failing
to
reject
H0
increases,
if
H0
is
true
 d) The
probability
of
failing
to
reject
H0
increases,
if
H1
is
true
 e) Both
A
and
B
are
true
 
 4. A
t‐test
is
used
in
place
of
a
z‐test
when
which
of
the
following
is
unknown?
 a) σ
 b) s
 c) μ
 d) α
 e) 
 
 5. When
is
the
mean
of
the
sampling
distribution
of
sample
means
equal
to
the
population
mean?
 a) When
the
population
from
which
samples
are
drawn
is
normally
distributed
 b) When
the
population
from
which
samples
are
drawn
is
not
normally
distributed,
but
the
 sample
sizes
are
greater
than
about
35
 c) When
the
sample
mean,
 X ,
is
equal
to
the
population
mean
 d) The
mean
of
the
sampling
distribution
of
sample
means
is
always
equal
to
the
 population
mean
 e) When
A
or
B
is
true
 
 
 
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 4
 For
the
following
five
questions,
assume
that
a
researcher
is
interested
in
finding
out
what
 substances
can
affect
exam
scores.

For
this
experiment,
the
researcher
is
specifically
interested
in
 whether
eating
ice
cream
before
an
exam
changes
students’
statistics
exam
scores.He
knows
that
 the
average
score
for
students
on
a
particular
exam
is
83%.

He
gives
ice
cream
cones
to
16
 randomly
selected
students
before
the
exam
and
finds
that
his
sample
has
a
mean
of
86%
and
 standard
deviation
of
5%.
 6. Which
hypothesis
test
should
the
researcher
perform?
 a) one
sample
z‐test
 b) one
sample
t­test
 c) independent
samples
t‐test
 d) dependent
samples
t‐test
 e) Cohen’s
d
test
 
 7. What
is
the
appropriate
alternative
hypothesis
for
this
test?
 a) Eating
ice
cream
before
an
exam
changes
students’
scores
 b) Eating
ice
cream
before
an
exam
decreases
students’
scores.
 c) Eating
ice
cream
before
an
exam
does
not
change
students’
scores.
 d) Eating
ice
cream
before
an
exam
increases
students’
scores.
 e) Any
of
the
above
could
be
the
alternative
hypothesis
 
 8. How
many
degrees
of
freedom
does
this
test
have?
 a) 16
 b) 15
 c) 14
 d) 30
 e) This
test
does
not
utilize
degrees
of
freedom
 
 9. What
is/are
the
critical
values
of
the
test
statistic
with
α
=
0.10?
 a) 1.753
 b) +
1.645
 c) +
1.746
 d) +
1.960
 e) +
1.753
 
 10. What
conclusion
should
the
researcher
draw?
 a) Accept
the
null
hypothesis
 b) Fail
to
reject
the
null
hypothesis
 c) Reject
the
null
hypothesis
 d) Prove
the
null
hypothesis
 e) Retain
the
null
hypothesis
 
 11. Which
of
the
following
pairs
is
equivalent
to
Alpha
(α)
and
Beta
(β),
respectively?
 a) Hit,
Correct
Rejection
 b) False
Alarm,
Correct
Rejection
 c) False
Alarm,
Miss
 d) Miss,
Hit
 e) False
Alarm,
Correct
Acceptance
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 5
 
 12. As
sample
size
increases,
the
distribution
of
sample
means
_______________.

 a) approaches
the
shape
of
a
normal
distribution
 b) becomes
equal
to
the
population
distribution
 c) becomes
more
narrow
(less
variable)
 d) all
of
the
above
 e) (a)
and
(c)
only
 
 13. Which
of
the
following
accurately
defines
a
Type
II
error?
 a) Rejecting
H0
when
H0
is
true
 b) Rejecting
H0
when
H0
is
false
 c) Failing
to
reject
H0
when
H0
is
true
 d) Failing
to
reject
H0
when
H0
is
false
 e) Both
C
and
D

 
 
 14. The
distribution
of
sample
means:
 a) Is
always
normally
distributed
 b) Is
normally
distributed
only
if
the
population
is
normally
distributed
 c) Is
normally
distributed
only
if
the
sample
is
normally
distributed
 d) Is
normally
distributed
only
if
the
sample
size
is
greater
than
about
35
 e) None
of
the
above
are
true
 15. Which
of
the
following
will
affect
Cohen’s
d?
 a) The
sample
size
of
a
study
 b) The
variability
in
the
population
 c) The
alpha
level
of
the
study
 d) Whether
hypotheses
are
directional
or
non‐directional

 e) All
of
the
above
will
affect
Cohen’s
d
 
 16. Which
of
the
following
most
precisely
describes
what
 
(the
standard
error
of
 X )
measures?
 a) The
standard
amount
that
scores
in
the
population
will
vary
around
the
population
 mean
 b) The
standard
amount
scores
in
a
sample
will
vary
around
the
population
mean
 c) The
standard
amount
means
of
samples
will
vary
around
the
population
mean
 d) The
standard
amount
any
statistic
of
a
sample
will
vary
around
the
population
 parameter
 e) The
standard
amount
the
mean
of
a
specific
sample
varied
around
the
population
mean
 
 17. Assume
we
are
performing
a
one
sample
t‐test.
μ
=
20, =
25,
and
s
=
10.
If
we
increase
the
size
 of
our
sample
from
n
=
10
to
n
=
30,
which
of
the
following
accurately
describes
what
will
 happen
to
the
probability
of
making
the
following
decision
errors?
 a) The
probability
of
a
type
I
error
would
increase,
if
H0
is
true.
 b) The
probability
of
a
type
II
error
would
increase,
if
H1
is
true
 c) The
probability
of
a
type
II
error
would
decrease,
if
H1
is
true
 d) The
probability
of
a
type
I
error
would
decrease,
if
H0
is
true
 e) Any
of
the
above
could
happen
 
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 6
 
 Dr.
Gold
N.
Tanner
visits
Pacific
beach
often
and
is
convinced
that
the
water
is
colder
than
usual
 whenever
he
decides
to
go.
Dr.
Tanner
starts
to
record
the
temperature
of
the
water
every
time
he
 goes
to
the
beach.

After
a
bit
of
research,
he
learns
that
the
daily
ocean
water
temperature
at
Pacific
 Beach
is
normally
distributed
with
a
mean
of
65
and
a
standard
deviation
of
4.

The
mean
 temperature
for
the
25
days
he
goes
to
the
beach
is
63.

Help
him
answer
the
following
two

 questions.
 18. What
is
the
(estimated)
standard
error?
 a) 0.16
 b) 0.80
 c) 4
 d) 12.50
 e) 65
 
 19. What
is
Dr.
Tanner’s
observed
test
statistic?
 a) 2.50
 b) ‐0.50
 c) ­2.50

 d) ‐12.5
 e) +0.50
 
 20. Which
of
the
following
is
the
correct
interpretation
of
the
following
statement
about
a
 hypothesis
test:
“A
statistically
significant
effect
of
drug
A
was
found,
p
<
.05”
 a) There
is
less
than
a
5%
chance
that
the
null
hypothesis
is
true
 b) There
is
a
95%
chance
that
the
alternative
hypothesis
is
true
 c) There
is
less
than
a
5%
chance
of
getting
the
observed
effect
if
the
null
hypothesis
 is
true
 d) There
is
95%
chance
of
getting
the
observed
effect
if
the
alternative
hypothesis
is
true
 e) Both
A
and
B
 
 21. Statistical
power
is:
 a) The
probability
of
rejecting
the
null
hypothesis
if
either
H0
or
H1
is
true
 b) One
minus
the
probability
of
a
Type
II
error
 c) The
probability
that
your
test
will
be
statistically
significant
if
the
effect
being
measured
 is
real
 d) All
of
the
above
 e) B
and
C
only
 
 22. The
data
from
an
independent‐measures
research
study
produce
a
sample
mean
difference
of
4
 points
and
a
pooled
variance
of
12.
If
there
are
n
=
6
scores
in
each
sample,
then
the
value
for
 the
t
statistic
is
____.
 a) 1.00
 b) 2.00
 c) 2.83
 d) 1.41
 e) 12.0
 
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 7
 23. For
a
repeated‐measures/dependent‐samples
test,
the
null
hypothesis
states:
 a) µ1 = µ2 
 b) µ1 − µ2 = 0 
 c) µ D − µ = 0 
 d) µ D = 0 
 e) µ D = X D 
 
 24. Which
of
the
following
will
increase
the
power
of
a
statistical
test?
 a) change
α
from
0.05
to
0.01
 b) change
the
sample
size
from
n
=
100
to
n
=
25
 c) increase
the
variance
in
the
population
 d) all
of
the
above
will
increase
power
 e) none
of
the
above
will
increase
power
 
 25. A
researcher
reports
t(24)
=
5.30
for
an
independent‐measures
experiment.
How
many
 individuals
participated
in
the
entire
experiment?
 a) 24
 b) 25
 c) 26
 d) 12
 e) 13
 
 26. What
is
the
estimated
standard
error
for
the
independent‐measures
t
statistic
for
the
following
 two
samples?
Sample
1:
n
=
4
with
SS
=
100.
Sample
2:
n
=
8
with
SS
=
140.
 a) 3
 b) 9
 c) 24
 d) 576
 e) 578
 
 27. For
which
of
the
following
situations
would
a
repeated‐measures
design
have
the
maximum
 advantage
over
an
independent‐measures
design
assuming
the
particular
study
could
be
 reasonably
conduced
either
way?
 a) when
many
subjects
are
available
and
individual
differences
are
small
 b) when
very
few
subjects
are
available
and
individual
differences
are
small
 c) when
many
subjects
are
available
and
individual
differences
are
large
 d) when
very
few
subjects
are
available
and
individual
differences
are
large
 e) For
none
of
the
above
situations
would
a
repeated‐measures
design
have
an
advantage
 over
an
independent
measures
design

 
 
 
 

 
 Make
sure
you
bubbled
in
correctly
which
Test
Form
you
were
taking.

 We
cannot
score
your
exam
without
this!
Before
continuing,
check
that
you
have
done
this.
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 8
 Short
Answer
and
Computation
Questions:
(7
points
total)
VER
A
 
 For
these
questions,
you
must
show
your
work
in
order
to
receive
any
credit.
If
you
are
using
a
 formula
to
solve
the
question,
write
the
formula
first,
and
then
apply
the
formula
to
the
problem.

 
 Write
legibly
and
CIRCLE
your
final
answer
for
each
question
 
 28. A
nutrition
store
in
the
mall
is
selling
"Memory
Booster,"
which
is
a
concoction
of
herbs
and
 minerals
that
is
intended
to
improve
memory
performance.
To
test
the
effectiveness
of
the
 herbal
mix,
a
researcher
obtains
a
sample
of
n
=
16
people
and
asks
each
person
to
take
the
 suggested
dosage
each
day
for
four
weeks.
This
researcher
is
interested
in
whether
the
herbal
 supplement
has
any
effect,
positive
or
negative.
At
the
end
of
the
four‐week
period,
each
 individual
takes
a
standardized
memory
test.
The
scores
from
the
sample
produce
a
mean
of
 
 =
26
with
SS
=
960.
In
the
general
population,
the
standardized
test
is
known
to
have
a
mean
of
 μ
=
20.
 a) State
the
appropriate
null
and
alternative
hypotheses
using
the
correct
symbols.
 
 H 0 : µafter = 20 
 H 1 : µafter ≠ 20 b) What
is/are
the
critical
value(s)
of
the
appropriate
test
statistic
for
this
experiment
 using
α
=
0.05?
 
 df = 15, α =0.05, t critical = ± 2.131 
 c) Compute
the
value
of
the
estimated
standard
error
 
 





 SS 960 s2 = = = 64 
 df 15 
 sX = 
 
 
 
 
 
 
 
 
 s2 64 = = 4 =2
 n 16 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 9
 
 d) Assuming
the
estimated
standard
error
=
1,
compute
the
value
of
the
appropriate
test
 statistic
for
this
experiment.

 DO
NOT
USE
ANY
OTHER
VALUE
FOR
THE
ESTIMATED
STADNARD
ERROR
 
 
 X−µ 26 − 20 tX = , tX = , tX = 6 
 sX 1 
 
 
 e) Interpret
the
result
from
part
D.
Do
you
have
evidence
that
“Memory
Booster”
affects
 memory
performance?
Be
sure
to
say
why
you
believe
you
do
or
do
not
have
evidence,
 and
use
the
correct
terminology
when
discussing
the
result.

 
 
 df = 15, α =0.05, t critical = ± 2.131 
 
 |tobserved|
>
|tcritical|,

6
>
2.131,
Reject
Null
Hypothesis
 
 
 
 29. Julian
wants
to
know
if
two
different
routes
he
can
take
to
campus
are
equivalent
in
terms
of
 the
time
each
takes
on
average
(a
serious
question,
indeed).
Over
twenty
days,
Julian
flips
a
coin
 when
he
gets
in
his
car
to
decide
which
route
he
will
take.
Below
are
the
data
(raw
data
and
 summary
data)
for
the
12
days
he
took
Route
A,
and
the
8
days
he
took
Route
B
(because
Julian
 decided
randomly
which
route
to
take,
he
ended
up
taking
route
A
more
times
during
the
20
 days).
Help
Julian
run
a
hypothesis
test
using
α
=
0.05.
 
 Route A Route B X = 13.000 X = 15.500 Minutes s2 = 6.364 n = 12 
 
 
 
 
 Minutes s2 = 2.500 n=8 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 
 a) State
the
appropriate
null
and
alternative
hypotheses
using
the
correct
symbols.
 
 H 0 : ( µroute A − µroute B ) = 0, or µroute A = µroute B 
 H 1 : ( µroute A − µroute B ) ≠ 0, or µroute A ≠ µroute B 
 
 b) What
is/are
the
critical
value(s)
of
the
appropriate
test
statistic
for
this
experiment?
 
 
 df = 18, α =0.05, t critical = ± 2.101 
 
 c) Calculate
the
estimated
standard
error

 2 sA = SSA SS SSB SS 2 , 6.364 = A ∴ SSA = 70 ,


 sB = , 2.5 = B ∴ SSB = 17.5 
 nA − 1 11 nB − 1 7 
 
 s 2 ed = pool SSA + SSB 70 + 17.5 2 87.5 , s 2 ed = , s pooled = , s 2 ed = 4.86 
 pool pool dfA + dfB 11 + 7 18 
 
 s( X1 − X2 ) = 
 
 
 
 
 
 
 
 s 2 ed pool n1 + s 2 ed pool n2 = 4.86 4.86 + = 0.405 + 0.6075 = 1.0125 , s( X1 − X2 ) = 1.006 
 12 8 10
 Psychology
60
–
Spring,
2010
–
Midterm
2
–
Given
5/18/2010
 11
 
 d) Assuming
the
estimated
standard
error
=
1,
compute
the
value
of
the
appropriate
test
 statistic
for
this
experiment.

 DO
NOT
USE
ANY
OTHER
VALUE
FOR
THE
ESTIMATED
STADNARD
ERROR

 
 
 






















 t( X1 − X2 ) = ( X1 − X2 ) 13 - 15.5 , t( X1 − X2 ) = , t( X1 − X2 ) = -2.5 
 s( X1 − X2 ) 1 
 





















or,
if
using
raw
data,
mean
for
Route
B
=
15.75

 
 ( X − X2 ) 13 - 15.75 




















 t( X1 − X2 ) = 1 , t( X1 − X2 ) = , t( X1 − X2 ) = -2.75 
 s( X1 − X2 ) 1 
 
 
 
 e) Interpret
the
results.
Is
there
sufficient
evidence
for
Julian
to
conclude
that
one
of
the
 two
routes
to
campus
is
faster?
Be
sure
to
say
why
you
believe
you
do
or
do
not
have
 evidence,
and
use
the
correct
terminology
when
discussing
the
result.
 
 
 















 df = 18, α =0.05, t critical = ± 2.101 
 
 























|tobserved|
>
|tcritical|,

2.5

>
2.101,




Reject
Null
Hypothesis
 




















 























or,
with
raw
data,

 























|tobserved|
>
|tcritical|,

2.75

>
2.101,




Reject
Null
Hypothesis
 
 
 
 
 
 ...
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