Ques 1
(a) p(AB)= p(B) p(A|B)=0.12
(b)p(AB)=p(A)+p(B)-p(AB)=0.88
(c) p(AcBc)=1- p(AB)=0.12
(d)p(B|A)= p(AB)/p(A)=0.12/0.40=0.30
Ques 2
(a) What is the probability this person is color-blind?
P( color blind) = P (color blind males) + P( color blind females

Problem 1. (3+ 5 +4 + 6+ 5 = 23) rFhe lifetime of a certain battery, denoted by X, has
a mean value of 8 hours and a standard deviation of 1 hour. There are 36 such batteries
in a package.
1. Can you ﬁnd the probability that the lifetime of one battery ex

Problem 1. (10+6+4+3+3=26 points) A sample of 23 high-school students is taken,
and the number of text messages they sent over the last ﬁve days is recorded,
52 85 87 55 92 25 76 69 83 62 43 95
84 91 92 7o 95 77 7e 83 74 51 83
use He Stem lecffﬂ' 205 as l

Quiz 9
Name_KEY_
An investigator predicts that dog owners in the country spend more time walking their dogs than
do dog owners in the city. The investigator gets a sample of 21 country owners and 23 city
owners. The mean number and standard deviation of h

Quiz 4
Name_Key_
Suppose X is a continuous random variable with probability density function (PDF)
c(1 x), 1 x 2
f ( x)
otherwise
0,
1. What is the value c so that
f (x )
above is a valid PDF?
f ( x) dx 1
x2 2 5
c(1 x ) dx [c( x ) |1 ] c 1
1
2
2
c 2

Quiz 5
Name_KEY_
Kim programs a computer to draw 200 random numbers, each number being a realization from a Poisson
distribution with = 4. Let X represent such a random number.
1. What is the probability that X = 0
e4 40 4
(
)
Answer: P X=0 = 0 ! =e =0.01

Quiz 8
Name_KEY_
The mean Verbal SAT score for the population of first students at Radford is 520. The standard
deviation of scores in this population is 95. An investigator believes that the mean Verbal SAT of
first year psychology majors is significantl

Quiz 6
Name_
1. In adults, 60% of pneumonia cases are caused by the pneumococcus bacterium. In a random
sample of n = 24 adults who have pneumonia, let X denote the number of people whose
pneumonia was caused by the pneumococcus bacterium.
(a)
Write down