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 give
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
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 a
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
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 -1.9
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
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
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
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 h