Chapter 8 problem #31
a. According to known condition, we can know that sample n=400 and responses
x=100. Therefore, we can work out that the point estimate of the proportion of
the population that would provide Yes responses is:
p=x/n=100/400=0.25
b. The
Chapter 10: Criminal Justice
Notes
2 Sample Testing
Sigma Known
Construction a Confidence Interval for
x1 x 2 z 2
Df =
n1 1 or n2 1
1 2
12 22
n1 n2
whichever is smaller
Sigma Unknown
Construction a Confidence Interval for
with Independent Samples
x1 x 2
Chapter 6 Problem #28
a. The expected number of adults who smoke is:
E(x)=25020%=50
b. The probability that fewer than 40 smoke is:
=(25020%(1-20%)^0.5=6.3246
P(x<40)=P(x39.5)=P(x-50)/6.3246(39.5-50)/6.3246)=P(z-1.66)=0.0485
c. We already getfrom part(b),
Chapter 1 Problem #3
a. According to known condition, we can find that the City MPG for each car is 13,
17, 16, 13, 24, 25, 17, 15, 21, and 21. Therefore, we can use these to work out the
average miles per gallon for city driving is 18.2 miles per gallon.
Chapter 7 problem #37
a. According to known condition, we can know that the p (the proportion of groceries
thrown out by
people) is 12% and n (sample) is 540. Therefore, we can calculate:
np=12%540=64.8
n(1-p)=540(1-12%)=475.2
So we can find that it accep
Chapter 7 problem #25
a. According to known condition, we can know that sample mean=E( )=502, n=90,
and =100.
Therefore, we can work out the standard deviation as follow:
100/(90^0.5)=10.541
And we already know that sample mean test score within 10 points
Chapter 5 Problem #41
a. According to known condition, we can find that n=20 and P=20%=0.2, so we can
compute the probability that 2 or fewer will withdraw and it is as follows:
P(x2)=P(x=0)+P(x=1)+P(x=2)
=[20!/0!20!(0.2)^0 (0.8)^20]+ [20!/1!19!(0.2)^1 (0
Chapter 5 Problem #15
a. For this question, we can use formula and known condition to compute E(x), the
expected value of x. The calculations as follow:
E(x)=3 0.25+60.50+90.25=6
b. From part (a), we can know that E(x)=6=, therefore, we can develop a tabl
Chapter 4 Problem #17
a. Refer to the KP&L sample points and sample point probabilities in Tables 4.2 and
4.3, we can see that three sample points in the event the design stage is over budget
and the sample points include (4, 6), (4, 7), (4, 8).
b. Refer
Chapter 3 Problem #7
a. For this question, we already know that the average commute time in minutes for
48 cities, so we can use these data and formula to calculate the mean commute time
for these 48 cities.
(23.3+28.3+24.6+32.1+31.7+25.8+38.1+24.9+26.8+2
Chapter 2 Problem #4
a. According to research, we can find that data that can be grouped by specific
categories are referred to as categorical data. For this question, data that can be
grouped by words, so these data are categorical.
b. According to known
Chapter 9: MBA Statistics
Notes
Hypothesis Testing
Basic Principles of Hypothesis Testing
Objectives
1. Define the null and alternate hypotheses
2. State conclusions to hypothesis tests
A hypothesis is a claim or statement about a property of a population