Statistics 305A
Quiz 1 September 20, 2007
Name
Instructor: Dr. Wu
_
Note: Points for each question are indicated in the left margin in square brackets.
1. The following data are the lifetimes (in months) of a sample of 8 electrical motors.
12.5, 14.4, 26.6, 18.0,7.3, 9.8,36.2,20.1
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(b) Give the coordinates of the two upper right points that would appear on a normal plot for these
data (on regular graph paper).
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(c) Draw a boxplot for these data. Use your calculations from part (a) and show any additional
calculations you need below. Be sure to carefully label numbers on the plot.
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(d) Find the sample mean and sample standard deviation for these data. Show your calculations.
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1
2. Consider data set #1: 5, 6, 7, 8 and data set #2: 8, 9, 10, 11, 12, 13. Find the coordinates of the two
lower left points that would appear on the Q-Q plot for the two data sets.
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3. For each of the following questions, circle only one answer. No credit will be received if more than one
is circled.
[18]
(a) A number of issues concerning measurement must be addressed in the following order:
(1) precision, validity, accuracy
(3) validity, accuracy, precision
(2) accuracy, precision, validity
(4) validity, precision, accuracy
(b) For a complete factorial study with three factors, each with 4 levels, the number of observations is
at least
(1) 12
(2) 64
(3) 81
(4) none of these
(c) Two students measured the outside diameter of each of five spanner bushings once using the same
caliper, resulting in 10 diameter measurements. These data can be best described as
(1) qualitative, paired
(2) quantitative, paired
(3) qualitative, univariate (4) quantitative, univariate
(d) For a 2 x 2 full factorial study with two factors A and B, each with two levels (low and high), the
four experimental runs are labeled as No.1: A low B low, No.2: A low B high, No.3: A high B
low, and No.4: A high B high. Based on the following random digits
417498314146502 1837863920
Which experiment should be done last?
(1) No.1
(2) No.2
(3) No.3
(4) No.4
(e) Based on the following random digits
46502 18314 16392 8551641749
the second widget selected from 30 widgets labeled 1,2, ... ,30 is
(1) 6
(2) 14
(3) 16
(4) none of these
(f) In a series of experiments to study the purity of a chemical product, the reactor temperature is set
at 550°C. The variable "reactor temperature" is a
(1) concomitant variable (2) controlled variable
(3) blocking variable (4) experimental variable
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