Devry MATH221 Week 3 Homework Latest 2019 JULY Question # 00603361 Course Code : MATH221 Subject: Mathematics Due on: 07/29/2019 Posted On: 07/29/2019 05:12 AM Tutorials: 1 Rating: 4.6/5

MATH221 Statistics for Decision Making

Week 3 Homework

Question 1Let
x represent the number of pets in pet stores. This would be considered what
type of variable:

Homework
Help:

3DA.
Discrete versus continuous variables (Links to an external site.) (DOCX)

Discrete

Nonsensical

Lagging

Continuous

Question 2Let x represent the height of corn
in Oklahoma. This would be considered what type of variable:

Homework
Help:

3DA.
Discrete versus continuous variables (Links to an external site.) (DOCX)

Distributed

Discrete

Continuous

Inferential

Question 3Consider the following table.

Age Group Frequency

18-29 9831

30-39 7845

40-49 6869

50-59 6323

60-69 5410

70 and over 5279

If you
created the probability distribution for these data, what would be the
probability of 40-49?

Homework
Help:

3DB.
Probabilities from a probability distribution (Links to an external site.)
(DOCX)

42.5%

23.7%

18.9%

16.5%

Question 4Consider the following table.

Weekly
hours worked Probability

1-30
(average=23) 0.08

31-40
(average=36) 0.16

41-50
(average=43) 0.72

51 and over
(average=54) 0.04

Find the mean of this variable.

Homework
Help:

3VA.
Calculating the mean, variance, and standard deviation of discrete variables
(Links to an external site.) (4:35)

3DC. Mean,
expected value, variance, and standard deviation of discrete variables (Links
to an external site.) (DOCX)

39.0

40.7

39.5

40.0

Question 5Consider
the following table.

Defects in
batch Probability

0 0.09

1 0.24

2 0.41

3 0.12

4 0.10

5 0.04

Find the variance of this variable.

Homework
Help:

3VA.
Calculating the mean, variance, and standard deviation of discrete variables
(Links to an external site.) (4:35)

3DC. Mean,
expected value, variance, and standard deviation of discrete variables (Links
to an external site.) (DOCX)

1.48

1.43

1.22

2.02

Question 6Consider the following table.

Defects in
batch Probability

2 0.18

3 0.29

4 0.18

5 0.14

6 0.11

7 0.10

Find the
standard deviation of this variable.

Homework
Help:

3VA.
Calculating the mean, variance, and standard deviation of discrete variables
(Links to an external site.) (4:35)

3DC. Mean,
expected value, variance, and standard deviation of discrete variables (Links
to an external site.) (DOCX)

2.49

1.52

4.01

1.58

Question 7The standard deviation of samples
from supplier A is 0.0841, while the standard deviation of samples from
supplier B is 0.0926. Which supplier would you be likely to choose based on
these data and why?

Homework
Help:

3DD.
Interpreting and comparing discrete variable standard deviations (Links to an
external site.) (DOCX)

Supplier B, as their standard deviation is
higher and, thus, easier to fit into our production line

Supplier B, as their standard deviation is
lower and, thus, easier to fit into our production line

Supplier A, as their standard deviation is
lower and, thus, easier to fit into our production line

Supplier A, as their standard deviation is
higher and, thus easier to fit into our production line

Question 8Ten frequent gamers are randomly
selected. The random variable represents the number of frequent gamers who play
video games on their smartphones. For this to be a binomial experiment, what
assumption needs to be made?

Homework
Help:

3DE.
Definitions, assumptions and elements (n, x, p) of binomial experiments (Links
to an external site.) (DOCX)

The probability of being a gamer and is
selected is the same for all gamers

The probability of being selected is the same
for all ten gamers

The probability of being a gamer that plays
video games on their smartphones is the same for all gamers

All ten selected gamers are the same age

Question 9A
survey found that 75% of all golfers play golf on the weekend. Eighteen golfers
are randomly selected. The random variable represents the number of golfers
that play on the weekends. What is the value of p?

Homework
Help:

3DE.
Definitions, assumptions and elements (n, x, p) of binomial experiments (Links
to an external site.) (DOCX)

75

0.75

0.18

x, the counter

Question 10Forty-four
percent of US adults have little confidence in their cars. You randomly select
twelve US adults. Find the probability that the number of US adults who have
little confidence in their cars is (1) exactly six and then find the
probability that it is (2) more than 7.

Homework
Help:

3VB.
Calculating binomial probabilities and cumulative probabilities (Links to an
external site.) (8:23)

3DF.
Binomial probabilities versus cumulative probabilities (Links to an external
site.) (DOCX)

(1) 0.207 (2) 0.901

(1) 0.762 (2) 0.901

(1) 0.793 (2) 0.099

(1) 0.207 (2) 0.099

Question 11Say a business found that 45% of
customers in Detroit, MI prefer green sweaters. The company chooses 8 customers
in Austin, TX and asks them if they prefer green sweaters. What assumption must
be made for this study to follow the probabilities of a binomial experiment?

Homework
Help:

3DE.
Definitions, assumptions and elements (n, x, p) of binomial experiments (Links
to an external site.) (DOCX)

That the probabilities of preferring green
sweaters is the same in both cities

That the probability of being a selected
customer is the same in both cities

That there is a 45% probability of being a
selected customer in either city

That the probability of preferring green
sweaters is the same as preferring sweaters from Austin

Question 12Seven baseballs are randomly
selected from the production line to see if their stitching is straight. Over
time, the company has found that 89.4% of all their baseballs have straight
stitching. If exactly five of the seven have straight stitching, should the
company stop the production line?

Homework
Help:

3VC. Using
binomials to assess quality of production (Links to an external site.) (3:08)

No, the probability of exactly five have
straight stitching is not unusual

Yes, the probability of five or less having
straight stitching is unusual

Yes, the probability of exactly five having
straight stitching is unusual

No, the probability of five or less having
straight stitching is not unusual

Question 13A bottling company puts 16 ounces
of water bottle in each bottle. The company has determined that 94% of bottles
have the correct amount. Which of the following describes a binomial experiment
that would determine the probability that a case of 12 cans has all cans that
are properly filled?

Homework
Help:

3DE.
Definitions, assumptions and elements (n, x, p) of binomial experiments (Links
to an external site.) (DOCX)

n=16, p=0.94, x=12

n=12, p=0.94, x=12

n=12, p=0.16, x=1

n=12, p=0.98, x=97

Question 14A
supplier must create metal rods that are 2.3 inches width to fit into the next
step of production. Can a binomial experiment be used to determine the
probability that the rods are the correct width or an incorrect width?

Homework
Help:

3VC. Using
binomials to assess quality of production (Links to an external site.) (3:08)

3DE.
Definitions, assumptions and elements (n, x, p) of binomial experiments. (DOCX)

Yes, all production line quality questions are
answered with binomial experiments

No, as there are three possible outcomes,
rather than two possible outcomes

Yes, as each rod measured would have two
outcomes: correct or incorrect

No, as the probability of being about right
could be different for each rod selected

Question 15In
a box of 12 pens, there is one that does not work. Employees take pens as
needed. The pens are returned once employees are done with them. You are the
5th employee to take a pen. Is this a binomial experiment?

Homework
Help:

3VC. Using
binomials to assess quality of production (Links to an external site.) (3:08)

3DE.
Definitions, assumptions and elements (n, x, p) of binomial experiments. (DOCX)

Yes, with replacement, the probability of
getting the one that does not work is the same

No, binomial does not include systematic
selection such as “fifth”

Yes, you are finding the probability of
exactly 5 not being broken

No, the probability of getting the broken pen
changes as there is no replacement

Question 16Eighty-two
percent of employees make judgements about their co-workers based on the
cleanliness of their desk. You randomly select 7 employees and ask them if they
judge co-workers based on this criterion. The random variable is the number of
employees who judge their co-workers by cleanliness. Which outcomes of this
binomial distribution would be considered unusual?

Homework
Help:

3VD.
Finding unusual outcomes from a probability distribution (Links to an external
site.) (2:32)

1, 2, 3, 4

0, 1, 2, 7

1, 2, 3

0, 1, 2, 3

Question 17Sixty-eight percent of products
come off the line within product specifications. Your quality control
department selects 15 products randomly from the line each hour. Looking at the
binomial distribution, if fewer than how many are within specifications would
require that the production line be shut down (unusual) and repaired?

Homework
Help:

3VD.
Finding unusual outcomes from a probability distribution (Links to an external
site.) (2:32)

Fewer than 9

Fewer than 8

Fewer than 10

Fewer than 11

Question 18The
probability of a potential employee passing a drug test is 86%. If you selected
12 potential employees and gave them a drug test, how many would you expect to
pass the test?

Homework
Help:

3DC. Mean,
expected value, variance, and standard deviation of discrete variables (Links
to an external site.) (DOCX)

9 employees

8 employees

11 employees

10 employees

Question 19The probability of a potential
employee passing a training course is 86%. If you selected 15 potential
employees and gave them the training course, what is the probability that more
than 12 will pass the test?

Homework
Help:

3VB.
Calculating binomial probabilities and cumulative probabilities (Links to an
external site.) (8:23)

0.648

0.852

0.900

0.352

Question 20Off
the production line, there is a 4.6% chance that a candle is defective. If the
company selected 50 candles off the line, what is the standard deviation of the
number of defective candles in the group?

Homework
Help:

3VA.
Calculating the mean, variance, and standard deviation of discrete variables
(Links to an external site.) (4:35)

2.30

1.10

1.48

2.19