CHAPTER 7 TUTORIALS
1. An electrical firm manufactures light bulbs that have a length of life that is normally
distributed with a standard deviation of 40 hours. A sample of 30 bulbs is taken and gives
an average life of 780 hours.
(a) Find a 96% confiden

1. State the null and alternative hypothesis for each of the following scenarios
a. About 10% of the human population is left-handed. Suppose a researcher at Penn
State speculates that students in the College of Arts and Architecture are more likely
to be

Question 1
Suppose Z N (0,1) . Find the value of
z
if you are given that
P ( 1.96< Z < z )=0.1001
Question 2
The marks for the Stats 130 course are known to follow a normal distribution with mean 55 and
variance 36. A random sample of 49 students is drawn

TUTORIAL 4
Question 1
Construct a sample space for each of the following experiments
a. The tossing of two dice simultaneously
b. The tossing of a coin 4 times
*
*
Question 2
Given the sample space
B=cfw_ 3, 10,11, 15
and
S= cfw_2,3,5,7,8,10,11,12,13,15

TUTORIAL 2 QUESTIONS
Question 1
The stem and leaf plot below shows the number of packages mailed by a small mail order
company on 26 consecutive business days.
1
5
2
3
0
1
9
4
0
2
3
7
8
8
5
0
1
2
4
5
6
6
1
5
7
8
7
2
4
9
8
5
9
3
9
Key: 1|5 = 15
a. Calculat

TUTORIAL 7
1. Find the area under a standard normal curve that is
a. To the left of 1.73
b. To the right of 1.24
c. To the right of -1.24
d. To the left of -1.24
e. To the left of 1.24
f. Between -1.96 and 1.96
2. Find the value of
z that whose
z is 0.267

TUTORIAL 5
1. A student goes to the library. The probability that she checks out (a) a work of fiction
is 0.40, (b) a work of non-fiction is 0.30, and (c) both fiction and non-fiction is 0.20.
What is the probability that the student checks out a work of

CHAPTER 1 TUTORIAL QUESTIONS
Question 1
The Department of Education was concerned about the schooling in some schools in a
particular area. Two hundred (200) students from these schools were randomly chosen to
write a standardized test. Their average test

1.
2. You are given the following probability distribution for a random variable X:
P ( X=2 )=0.05 ; P ( X =0 )=0.15 ;
P ( X=2 ) =0.6
and
P ( X=4 ) =0.2
What is the standard deviation of X?
3.
4.
Use the table below to answer questions 5,6, and 7
The cumu

TUTORIAL 3 QUESTIONS
Question 1
The following ogive shows the dividend yields (in Rands) for 28 common stocks.
a. What is the 3rd decile (
D3
) for this data set?
b. Forty (40) percent of the stocks have (approximate) dividend yields of at least which
val