10. Which of the following variables is discrete? (LO6)
a) Number of students in a class
b) Height of students in a class
c) Name of students in a class
d) Lifetime of a certain type of battery
e) none of these
11. If scores of the students are normally distributed with a mean 60 and a standard deviation of 4 . What percent of the scores is greater than 602 (LO6)
a) \( 40 \% \)
b) \( 50 \% \)
c) \( 60 \% \)
d) \( 55 \% \)
e) none of these
12. If scores of the students are nomally distributed with a mean 60 and a standard deviation of 4 . What is the probability that a selected student's score is at least 647 (LO6)
a) 0.8413
b) 0.3821
c) 0.1841
d) 0.1587
e) none of these
13. Given a standard normal distribution, which of the following is the value of \( k \) such that \( P(-2<Z<k)=0.9272 \) ? Interpolate where appropriate. (LO6)
a) 2.60
b) -0.75
c) 1.645
d) 2.565
e) none of these
14. Let \( X \) denotes the amount of grams of hydrocarbons emitted by an automobile per mile. Assuming that \( X \) is normal random variable with \( \mu=1 \) gram and \( \sigma=0.25 \) gram, find the probability that a randomly selected automobile will emit between 0.50 and 1.50 grams of hydrocarbons per mile. (LO6)
a) 0.9544
b) 0.0228
c) 0.6826
d) 0.1587
e) 0.9974
15. Determine the value of \( c \) so that the following function represents joint probability distribution of the discrete random variables \( X \) and \( Y \) :
\[
\begin{array}{l}
X \text { and } Y: \\
f(x, y)=c|x-y|, \text { for } x=-1,0,1 ; \quad y=1,2 .
\end{array}
\]
a) \( 1 / 10 \)
b)1/11
c) \( 1 / 36 \)
d) \( 1 / 8 \)
e) \( 1 / 9 \)
The following joint probability distribution for discrete random variables, \( X \) and \( Y \), is used in questions 16,17 \& 1
Suppose \( X \) and \( Y \) have the following joint probability distribution
\begin{tabular}{l|llll}
\( p(x, y) \) & 1 & \( 2^{y} \) & 3 \\
\hline\( x \) & 1 & 0.10 & 0.22 & 0.08 \\
\( x \) & 2 & 0.33 & 0.12 & 0.15
\end{tabular}
16. Find \( P(X+Y \leq 4) \) (LO7)
a) 0.43
b) 0.77
c) 0.23
d) 0.85
e) 0.15
17. Find \( P(X=1) \). (LO7)
a) 0.40
b) 0.55
c) 0.43
d) 0.30
e) 0.34
18. Find \( P(Y=1) \).(LO7)
a) 0.60
b) 0.55
c) 0.40
d) 0.30
e) 0.43
19. Which of the following is an example of ratio-level data? (LO6)
a) Temperature
b) Weight
c) Ranking of tennis players
d) Gender
e) none of these
Booklet A
