WEBDISTANCE
ST 370
Quiz 1
Autumn 2007
ver.
A
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PROBLEM 1:
If
the number 3
is added to every member of a sample of observations
(as might happen if an ohm meter was not zeroed before doing measurements) THEN
a)
the sample mean does not change
b)
the sample median does not change
c)
the sample standard deviation of the sample does not change
d)
the sample variance is increased by 9 times
e)
the sample variance is increased by 3 times
PROBLEMS 2 and 3:
A sample of 5 cars parked along the
Hillsborough Street across
from the library revealed the following data on the NUMBER OF M&M’s on the floor
under the passengerside seat
33,
7,
3,
54,
12
2)
The value of the
(Sample Mean
MINUS
the
Sample median)
for
this dataset
is :
a) 12.3
b)
5.2
c)
9.8
d)
18.5
e) none of these
3)
What is the
37
th
percentile for this dataset
a)
7.4
b)
8.1
c)
8.4
d)
9.6
e) none of these
PROBLEM 4)
How is the correlation coefficient r related to the least squares slope b
a)
r = b s
Y
/ s
X
b)
r = b s
X
/ s
Y
c)
r = s
X
/ (b s
Y
)
d)
r = s
Y
/( b s
X
)
e)
none of these
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View Full DocumentPROBLEM 5)
A data set for precipitation has 86 observations and the stem and
leaf plot is given below.
The 75th percentile is
a)
3.62
b)
3.70
c)
3.78
d)
3.84
e)
4.26
LEAF ( LAST DIGIT)
0. 3 3 4 5 6 7 7 8
1. 0 1 2 2 2 5 5 6 8 8 8
Stem
2. 0 0 1 2 2 2 3 4 4 6 6 6 7 7 8 9 9 9 9 9 9 9 9
3. 0 1 1 1 2 2 2 3 3 3 3 4 4 4 4 5 6 6 6 6 6 6 7 7 7 8 8
9 9
4. 0 0 0 0 0 1 2 4 5 8
5. 0 4 4 8 9
PROBLEM 6)
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 Fall '08
 Nail
 Standard Deviation, #, 20 feet

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