Homework 10

Homework 10 - Homework
Assignment
10
 NOT
GRADED


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Unformatted text preview: Homework
Assignment
10
 NOT
GRADED
 Answers
will
be
available
Friday

 
 
 
 
 Psychology
60
 Spring
2010
 1. What
information
does
the
sign
of
the
Pearson
correlation
provide?
How
does
this
 information
relate
to
the
sign
of
the
slope
(b)
and
will
they
always
correspond?

 
 2. Calculate
the
sum
of
products
(SP)
for
the
following
set
of
scores:
 X

 2
 6
 1
 3
 Y
 4
 3
 8
 5
 3. Assuming
that
you
are
running
a
two‐tailed
test
with
alpha
=
0.05,
how
large
of
a
correlation
 is
needed
to
be
statistically
significant
or
each
of
the
following
samples?
 a. A
sample
of
n
=
10
 b. A
sample
of
n
=
20
 c. A
sample
of
n
=
30
 
 4. The
regression
equation
is
intended
to
be
the
best
fitting
straight
line
for
a
set
of
data.
What
 is
the
criterion
for
“best
fitting”
?
 
 ˆ 5. For
the
following
scores,
find
the
best
fitting
line,
and
find
the
predicted
values
of
Y
( Yi )
at
 each
X
score
(that
is,
what
values
the
fitted
line
predicts
for
each
observed
value
of
X)
 
 X
 Y
 3
 0
 8
 10
 7
 8
 5
 3
 7
 7
 6
 8
 
 6. A
set
of
n
=
20
pairs
of
scores
(X
and
Y
values)
has
SSx
=
25,
SSY
=
16,
and
SP
=
12.50.
If
the
 mean
for
the
X
values
is
 X = 6 
and
the
mean
for
the
Y
values
is
 Y = 4 
 a. Find
the
best
fitting
line
for
these
data
 b. Calculate
the
Pearson
correlation
for
the
scores
 c. Assuming
everything
else
stays
the
same,
does
the
value
of
the
Pearson
correlation
 coefficient
change
if
the
mean
for
the
X
values
is
now
 X = 600 
and
the
mean
for
the
Y
 values
is
 Y = 400 ?
Why
or
why
not?
 d. Assuming
these
data
represent
a
sample
from
some
population,
do
we
have
evidence
 that
there
is
a
linear
relationship
in
the
population
from
which
the
sample
is
drawn?

 ...
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This note was uploaded on 10/16/2011 for the course PSYCH 60 taught by Professor Parris during the Spring '11 term at UCSD.

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