Search & Filtering
of the salary for of commercial Danks is normally distributed with mean 900,000 per month Also standardized value of What is the probability that randomly selected eams per month?
A manufacturer of electronic components is in-
terested in determining the lifetime of a certain type
of battery. A sample, in hours of life, is as follows:
123, 116, 122, 110, 175, 126, 125, 111, 118, 117.
(a) Find the sample mean and median.
(b) What feature in this data set is responsible for the
substantial difference between the two?
The hydrocarbon emissions at idling speed in
parts per million (ppm) for automobiles of 1980 and
1990 model years are given for 20 randomly selected
cars.
1980 models:
141 359 247 940 882 494 306 210 105 880
200 223 188 940 241 190 300 435 241 380
1990 models:
140 160 20 20 223 60 20 95 360 70
220 400 217 58 235 380 200 175 85 65
(a) Construct a dot plot as in Figure 1.1.
(b) Compute the sample means for the two years and
superimpose the two means on the plots.
(c) Comment on what the dot plot indicates regarding
whether or not the population emissions changed
from 1980 to 1990. Use the concept of variability
in your comments.
Group Project: Collect the shoe size of every-
one in the class. Use the sample means and variances
and the types of plots presented in this chapter to sum-
marize any features that draw a distinction between the
distributions of shoe sizes for males and females. Do
the same for the height of everyone in the class.
Which of the following events are equal?
(a) A = {1, 3};
(b) B = {x | x is a number on a die};
(c) C = {x | x2 − 4x +3=0};
(d) D = {x | x is the number of heads when six coins
are tossed}.
Construct a Venn diagram to illustrate the pos-
sible intersections and unions for the following events
relative to the sample space consisting of all automo-
biles made in the United States.
F : Four door, S : Sun roof, P : Power steering.
If an experiment consists of throwing a die and
then drawing a letter at random from the English
alphabet, how many points are there in the sample
space?
If a multiple-choice test consists of 5 questions,
each with 4 possible answers of which only 1 is correct,
(a) in how many different ways can a student check off
one answer to each question?
(b) in how many ways can a student check off one
answer to each question and get all the answers
wrong?
In how many ways can 5 different trees be
planted in a circle?
Which of the following events are equal?
(a) A = {1, 3};
(b) B = {x | x is a number on a die};
(c) C = {x | x2 − 4x +3=0};
(d) D = {x | x is the number of heads when six coins
are tossed}.
