Chapter 1: Overview and Descriptive Statistics
CHAPTER 1
Section 1.1
1. a. b. c. d. Houston Chronicle, Des Moines Register, Chicago Tribune, Washington Post Capital One, Campbell Soup, Merrill Lynch, Pulitzer Bill Jasper, Kay Reinke, Helen Ford, Dav
CHAPTER 6
Section 6.1
1. a. We use the sample mean,
x to estimate the population mean .
^ =x=
b.
xi 219.80 = = 8.1407 n 27
We use the sample median, ascending order).
~ = 7.7 (the middle observation when arranged in x
1860.94 - ( 219.8) 27 s =
CHAPTER 8
Section 8.1
1. a. b. c. d. Yes. It is an assertion about the value of a parameter. No. The sample median
~ X is not a parameter.
No. The sample standard deviation s is not a parameter. Yes. The assertion is that the standard deviation of
CHAPTER 11
Section 11.1
1. a.
30.6 59.2 7.65 = 7.65 , MSE = = 4.93 , f A = = 1.55 . Since 1.55 is 4 12 4.93 not F. 05, 4 ,12 = 3.26 , don't reject HoA . There is no difference in true average tire MSA =
lifetime due to different makes of cars.
b.
CHAPTER 10
Section 10.1
1. a. Ho will be rejected if
f F.05, 4,15 = 3.06 (since I 1 = 4, and I ( J 1 ) = (5)(3) = 15 ).
The computed value of F is
f =
3.06 , Ho is not rejected. The data does not indicate a difference in the mean tensile stre
CHAPTER 12
Section 12.1
1. a. Stem and Leaf display of temp: 17 0 17 23 17 445 17 67 17 18 0000011 18 2222 18 445 18 6 18 8
stem = tens leaf = ones
180 appears to be a typical value for this data. The distribution is reasonably symmetric in appeara
CHAPTER 16
Section 16.1
1. All ten values of the quality statistic are between the two control limits, so no out-of-control signal is generated.
2.
All ten values are between the two control limits. However, it is readily verified that all but one
CHAPTER 15
Section 15.1
1.
H 0 : = 100 vs. H a : 100 . The test statistic is s + = sum of the ranks associated with the positive values of ( xi - 100) , and we reject Ho at significance level .05 if s + 64 . (from Table A.13, n = 12, with / 2 =
CHAPTER 14
Section 14.1
1. a. We reject Ho if the calculated
2 value is greater than or equal to the tabled value of
2 , k -1 from Table A.7. Since 12.25 .2 , 4 = 9.488 , we would reject Ho . 05
b. c. d.
Since 8.54 is not Since 4.36 is not
CHAPTER 13
Section 13.1
1. a.
2 ^i is 10 1 - 1 - (x i - 15 ) = = 250 , so s.d. of Yi - Y 5 250
x = 15
and
(x
j
- x)
2
6.32, 8.37, 8.94, 8.37, and 6.32 for i = 1, 2, 3, 4, 5. b. Now
x = 20 and
(x
i
- x ) = 1250 , giving standard deviation
CHAPTER 5
Section 5.1
1. a. b. c. P(X = 1, Y = 1) = p(1,1) = .20 P(X 1 and Y 1) = p(0,0) + p(0,1) + p(1,0) + p(1,1) = .42 At least one hose is in use at both islands. P(X 0 and Y 0) = p(1,1) + p(1,2) + p(2,1) + p(2,2) = .70 By summing row probabi
CHAPTER 7
Section 7.1
1. a.
z 2 = 2.81 implies that 2 = 1 - (2.81) = .0025 , so = .005 and the confidence
level is 100 1 -
(
)% = 99.5% .
b. c.
z 2 = 1.44 for = 2[1 - (1.44)] = .15 , and 100(1 - )% = 85% .
99.7% implies that
= .003 , 2
CHAPTER 9
Section 9.1
1. a.
E (X - Y ) = E( X ) - E (Y ) = 4.1 - 4.5 = -.4 , irrespective of sample sizes.
V ( X - Y ) = V (X ) + V (Y ) =
of
2 12 2 (1 .8) (2.0) = .0724 , and the s.d. + = + m n 100 100 2 2
b.
X - Y = .0724 = .2691 .
c.
A norm
CHAPTER 3
Section 3.1
1. S: X: FFF 0 SFF 1 FSF 1 FFS 1 FSS 2 SFS 2 SSF 2 SSS 3
2.
X = 1 if a randomly selected book is non-fiction and X = 0 otherwise X = 1 if a randomly selected executive is a female and X = 0 otherwise X = 1 if a randomly select
CHAPTER 2
Section 2.1
1.
a. S = { 1324, 1342, 1423, 1432, 2314, 2341, 2413, 2431, 3124, 3142, 4123, 4132, 3214, 3241, 4213, 4231 } Event A contains the outcomes where 1 is first in the list: A = { 1324, 1342, 1423, 1432 } Event B contains the outcome