ISyE2028A, Fall 2010
Tuesday September 28
Midterm 1 Solutions
Version A
1.
The median of the data set 8, 20, 18, 8, 9, 16, 10, and 12 is __________.
[5 points]
ANSWER: 11
2.
The positive square root of the population variance is called __________.
[5 points]
ANSWER: population standard deviation
3.
Which of the following statement is false?
[5 points]
A.
A physical interpretation of the sample mean
x
demonstrates how it measures the location
(center) of a sample.
B.
The sample median, represented by
,
x
is the middle value when the observations are ordered
from smallest to largest.
C.
The sample median is very sensitive to extremely small or extremely large data values (outliers).
D.
The sample mean is very sensitive to extremely small or extremely large data values (outliers).
ANSWER: C
4.
Which of the following statement is not always true?
[5 points]
A.
A point estimator
ˆ
is said to be an unbiased estimator of parameter
if
ˆ
()
E
for every
possible value of
.
B.
If the estimator
ˆ
is not unbiased of parameter
, the difference
ˆ
E
is called the bias of
ˆ
.
C.
A point estimator
ˆ
is unbiased if its probability sampling distribution is always “centered” at
the true value of the parameter
, where “centered” here means that the median of the
distribution of
ˆ
is
.
ANSWER: C
5.
Which of the following expressions are true about a largesample upper confidence bound for the
population mean
?
[5 points]
A.
/2
x
z
s n
B.
x
z
s n
C.
x
z
s n
D.
x
z
s n
ANSWER: D
6.
The upper limit of a 95% confidence interval for the variance
2
of a normal population using a
sample of size
n
and variance value
2
s
is given by:
[5 points]
A.
22
.05,
1
(
1)
/
n
ns
B.
.025,
1
(
/
n
C.
.95,
1
(
/
n
D.
.975,
1
(
/
n
ANSWER: D
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentISyE2028A, Fall 2010
Tuesday September 28
7.
Measurements were made on the legs (in mm) of a random sample of certain species of beetles
regularly found on corn plants in Iowa.
The ordered data are as following:
Length of legs of certain beetle. (in mm)
121 125 130 130 130 131 131 132 135 135 137 138 138 141 143 143
145 146 147 151 163
A.
Create the stemandleaf plot.
B.
Construct the boxplot.
C.
Calculate a trimmed mean by deleting the smallest and largest observations.
What is the
corresponding trimming percentage?
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '07
 SHIM
 Normal Distribution, Standard Deviation, Mean

Click to edit the document details