comment kimberly

 

  I NEED A POSITIVE COMMENT BASED IN THIS ARGUMENT..BETWEEN 150-200 WORDS

 

A level of significance is a value that we set to determine statistical significance. This is ends up being the standard by which we measure the calculated  p-value of our test statistic. To say that a result is statistically significant at the level alpha just means that the p-value is less than alpha.

For instance, for a value of alpha = 0.05, if the p-value is greater than 0.05, then we fail to reject the null hypothesis.

There are some instances in which we would need a very small  p-value to reject a null hypothesis. If our null hypothesis concerns something that is widely accepted as true, then there must be a high degree of evidence in favor of rejecting the null hypothesis. This is provided by a p-value that is much smaller than the commonly used values for alpha.

Alpha is the term used to express the level of significance we will accept. For 95% confidence, alpha=0.05. For 99% confidence, alpha=0.01. These two alpha values are the ones most frequently used. If our P-value, the high unlikeliness of the H 0, is less than alpha, we can reject the null hypothesis. Alpha and beta usually cannot both be minimized—there is a trade-off between the two. Ideally, of course, we would minimize both. Historically, a fixed level of significance was selected (alpha=0.05 for the social sciences and alpha=0.01 or alpha=0.001 for the natural sciences, for instance). This was because the null hypothesis was considered the “current theory” and the size of Type I errors was much more important than that of Type II errors. Now both are usually considered together when determining an adequately sized sample. Instead of testing against a fixed level of alpha, now the P-value is often reported. Obviously, the smaller the P-value, the stronger the evidence (higher significance, smaller alpha) provided by the data is against H 0.

Example:  We took 10 samples of 20 pennies set on edge and the table banged. The resultant mean of heads was 14.5 with a standard deviation of 2.12. Since this is a small sample, and the population variance is unknown, after we calculate a t value and obtain t=6.71=(14.5-10)/(2.12/ (10)), we apply the t-test and find a P-value of either 8.73×10-5 or 4.36×10-5depending on whether we do a one-tailed or two-tailed test. In either case our results are statistically significant at the 0.0001 level.

Reference:

Calkins, Keith G. 2005. Applied Statistics Hypothesis Testing.  Retrieved from https://www.andrews.edu/~calkins/math/edrm611/edrm08.htm

 

 

 

                                

 

 

statitistics homework

Module 6 Homework Assignment

1.  Determine whether the samples are independent or dependent.

The effectiveness of a new headache medicine is tested by measuring the amount of time before the headache is cured for patients who use the medicine and another group of patients who use a placebo drug. Please explain your decision.

Solution:

 

Instructor Comments:


2. 
Determine whether the samples are independent or dependent.

The effectiveness of a headache medicine is tested by measuring the intensity of a headache in patients before and after drug treatment. The data consist of before and after intensities for each patient.

Please explain your decision.

Solution:

 

 

 

Instructor Comments:

 

3.  In a random sample of 500 people aged 20-24, 22% were smokers. In a random sample of 450 people aged 25-29, 14% were smokers. Test the claim that the proportion of smokers in the two age groups is the same. Use a significance level of 0.01. (Show all steps of the hypothesis test and all calculations) 

 

Solution:

 

 

 

Instructor Comments:

 

4.  A researcher wishes to determine whether people with high blood pressure can reduce their blood pressure by following a particular diet. The sample data is shown below, where μ1 represents the mean blood pressure of the treatment group and μ2 represents the mean for the control group. Use a significance level of 0.01 and whichever method you deem appropriate (p-value method, critical value method, or confidence interval method) to test the claim that the diet reduces the blood pressure. We do not know the values of the population standard deviations. Use Microsoft Excel or the following t-distribution table: http://www.itl.nist.gov/div898/handbook/eda/section3/eda3672.htm  

 

Treatment Group

Control Group

n1

85

n2

75

 

189.1

 

203.7

s1

38.7

s2

39.2

 

 

 

 

 

Solution:

 

 

Instructor Comments:

Stats help

How many times have you heard at the airport : “The plane is overbooked”
To the average person this sounds ridiculous. Why would they sell more
tickets than seats on the plane? The answer to this business practice 
lies within a binomial experiment exhibited by the following fictitious 
problem:

An airline sells 15 tickets for a small plane with 12 
seats. Overbooking is a common practice at this airline since only 80% 
of passengers that book and pay for a flight usually show up. Even 
though tickets are non-refundable, the airline wants to make more money.

N = number of tickets sold
p = probability a passenger shows up
q = probability a passenger does not show up.

  FIVE Part Posting Assignment

Part 1: Fill in the Blanks

N = _____, p = _____, q = _____

Part 2: Find the probability exactly 12 passengers show up 
(Must show work and/or calculator function and numbers used for your answer)

Part 3Find the probability more than 12 passengers show up
(Must show work and/or calculator function and numbers used for your answer)

Part 4Find the probability  less than 12 passengers show up
(Must show work and/or calculator function and numbers used for your answer)

Part 5Using your statistical and numerical findings above, write a statement (small letter) to the President of the Airline Company with your statistical recommendation for continuing, discontinuing, or changing their overbooking policy.  give reason for your recommendation.  Be clear.  Your statement should also include other considerations to take into account that may need further study.

OTHER INFORMATION
 (Work Hint:  I am looking for calculations and work such as the calculations presented in the video link for section 4.2 in the Instructor Comments.  Instead of “oatmeal raisin cookies”, you will do some calculations relating to this airlines example).

 

 

PLEASE SHOW WORK!!!!!

Order to remittance (OTR) time for hardware / software installations

 

The data in below table lists country code and the order to remittance (OTR) time for hardware / software installations for the last 76 installations (from first to last). OTR is the time it takes from an order being placed until the system is installed and we receive payment (remittance). Because this company does business internationally, it also notes the country of installation using a country code. This code is listed in the first column.

 

 

 

Table: Country Code and OTR Cycle Time for Software Systems Installation

 

Country Code

Cycle Time

Country Code

Cycle Time

1

20

5

29

1

24

6

40

1

46

7

157

1

26

8

19

14

38

5

24

1

15

1

81

1

15

7

53

17

23

7

26

1

31

1

28

1

31

1

34

6

64

1

34

5

29

7

50

5

44

1

52

1

32

1

19

1

15

1

44

7

11

14

150

7

14

7

29

1

89

17

23

17

41

6

79

7

41

17

13

1

36

6

32

8

43

7

61

17

21

8

42

8

28

8

46

7

18

7

88

8

47

14

24

6

26

7

7

6

47

1

33

5

9

5

129

7

42

17

41

5

5

17

43

6

27

14

42

6

27

14

42

1

33

7

53

7

44

7

53

1

21

7

48

1

22

5

21

1

50

1

19

 

 

 

 

 

Use the date in table above and answer the following questions in the space provided below:

 

  1. Does the OTR time appear to be stable?  Why or why not?

  2. If you were to use a control chart to evaluate stability, which chart would you use?  Why?

  3. What can you learn about the distribution of the installation process? 

  4. Does it appear that the country has an impact on installation time? Why or why not?

 

comment debbian T

 

 I NEED A POSITIVE COMMENT BASED IN THIS ARGUMENT..BETWEEN 150-200 WORDS

 

 

How would you explain the analysis of variance, assuming that your audience has not had a statistics class before?

ANOVA tells you if a set of features reduces the amount of unexplained information more by having the groupings than by leaving out all groupings.

A T-test is used to test differences between two means. For an example, the mean of the experiment group vs a control group. An ANOVA test, on the other hand, is indicated when there are three or more means or populations to be examined.

When only two samples are looked at, the T- test and ANOVA test will yield the same results.

Beyond two examples, the T – test can be used to evaluate other means using many T – test, but this method becomes unreliable and subject to increased error.

ANOVA or analysis of variance allows one to use statistics to test the differences between two or more means and decreases the probability for a type 1 error, which might occur when looking at multiple two-sample T – test. Therefore, ANOVA is indicated for testing hypotheses where there are multiple means or populations (Making Connections:The Two-Sample t-Test,Regression, and ANOVA).

The analysis of variance is carried out by the following: Population variance is estimated by variance among sample means. A second estimate of variance is made from variance within samples, comparing these two estimates of variance. If they are approximately equal in value, it is inferred that the means are not significantly different (Making Connections:The Two-Sample t-Test,Regression, and ANOVA).  

 

Reference:

Making Connections:The Two-Sample t-Test,Regression, and ANOVA. (n.d.). Retrieved March 18, 2015, from Pearson Highered: http://www.pearsonhighered.com/kuiper1einfo/assets/pdf/Kuiper_Ch02.pdf

 

 

comment jessica T

 

 I NEED A POSITIVE COMMENT BASED IN THIS ARGUMENT..BETWEEN 150-200 WORDS

 

 

An analysis of variance (ANOVA) evaluates the different groups in a study to determine if there are differences between the groups. The results tell us if there is a difference noted either between groups or between several intervals on one group. Unlike the t-test, the analysis of variance can be used on more than two groups.

However, in order to utilize the ANOVA, the groups must meet the following criteria:

The samples are normally distributed with equal variance, the groups are mutually exclusive (are different from one another), the dependent variables are measured on an interval or ratio scale, and all observations in each group are independent (not related to each other)

 

Example: If we want to compare the effects of blood pressure reducing methods on a group of patients.

We can divide a group of 40 into four groups. Group 1 takes furosemide only; Group 2 takes furosemide and meditates; Group 3 meditates; Group 4 is the control and has no intervention.

Using ANOVA we can evaluate all four groups at once. This is not possible with the t-test, nor would we want to use it as we would need to do multiple calculations increasing our risk of incorrectly rejecting the null hypothesis.

 

Reference:

 

Grove, S.K., Cipher, D. (2017). Statistics for nursing research: A workbook for evidence-based

practice (2nd ed) (pp. 377-378). St. Louis, MO: Elsevier. Saunders, 022016. VitalBook file Retrieved from: https://bookshelf.vitalsource.com/books/9780323358811/epubcfi/6/2%5B%3Bvnd.vst.idref%3Did_html-cover-page%5D!/4/8%5BcaretDiv%5D%400:268

 

ASAP

1. [15 pts.] When buyers purchase new houses, they are frequently responsible for installing their own landscaping. The PERT/CPM network shown in the accompanying figure represents a landscaping project for a new home in Jackson, Mississippi. The times are in days.

a. What are the expected completion time and the critical path for the landscaping project?
b. What are the earliest and latest start and finish times for activity C?
c. How long can activity A be delayed without delaying the minimum completion time of the project?
d. If activities A, C, and F are each delayed three days, how long will the landscaping project be delayed?

2. [10 pts.] Virtual Golf, Inc. (VGI) is contemplating introducing a new virtual reality golf experience that would, if successful, be located in many amusement parks and entertainment centers throughout the country. If the project gets the “go ahead”, it must be completed within 20 weeks (140 days) to be installed in the Mall of America in Bloomington, Minnesota, for test marketing. The table below gives cost and time estimates (in days) for the activities of the project.

Activity Immediate
Predecessors
A. Feasibility study –
B. Input from golf professionals A
C. Conceptual design B
D. Professional Feedback C
E. Final design D
F. Manufacture of unit E
G. Software development E
H. Equipment/software coordination F,G
I. In-house unit testing H
J. Operator training H
K. Construct unit in mall store I, J
L. Testing of unit in mall store K

Activity Normal Days Crash Days Normal Cost Crash Cost
A. Feasibility study 14 12 $15,000 $17,500
B. Input from golf professionals 14 11 $55,000 $64,000
C. Conceptual design 8 8 $50,000 $50,000
D. Professional Feedback 12 9 $40,000 $50,000
E. Final design 18 16 $50,000 $65,000
F. Manufacture of unit 20 16 $40,000 $55,000
G. Software development 14 10 $55,000 $70,000
H. Equipment/software coordination 21 19 $25,000 $65,000
I. In-house unit testing 10 8 $25,000 $32,000
J. Operator training 21 21 $50,000 $50,000
K. Construct unit in mall store 9 6 $25,000 $40,000
L. Testing of unit in mall store 15 10 $10,000 $40,000
a. What is the minimum project cost that will allow the project to be completed within 21 weeks?
b. What is the minimum project cost that will allow the project to be completed within 19 weeks?

3. [10 pts.] Consider the project facing VGI in Problem 2. If the company allocated a maximum of $450,000 to this project, what is the minimum time it would take to complete the project?

4. [25 pts.] Universal Travel is planning to move its headquarters from Cincinnati to Columbus, Ohio. The table below details the steps that must be taken. Times are in weeks.

Immediate Predecessors Optimistic Time Most Likely Time Pessimistic Time
A. Select a site – 8 12 20
B. Refurbish building A 9 10 12
C. Determine which staff will transfer – 2 2 3
D. Hire staff replacements in Columbus C 3 6 8
E. Pack boxes in Cincinnati A,C 1 2 5
F. Move equipment B 2 3 4
G. Move files B,E 1 2 5
H. Set up equipment/files in Columbus F,G 3 4 5
I. Occupancy D,H 5 6 10
a. What is the expected completion time of the project? What is the critical path?
b. What is the probability the project will be completed within 36 weeks?
c. Suppose Universal will be charged for both sites if it is not completely moved in within 36 weeks. This will cost the company $5,000. The company is considering two options to improve its chances to meet this deadline.
– For $1,000, additional movers can be hired to move the files. This would cut each of the three time estimates for that activity in half.
– Additional movers can be hired for $1,000 to assist in moving the equipment. This would cut the three time estimates for that activity by one week each.
The company can pursue either OR BOTH of these options. What is your recommendation?

comment debbian

 

 I NEED A POSITIVE COMMENT BASED IN THIS ARGUMENT..BETWEEN 150-200 WORDS

 

How would you explain the analysis of variance, assuming that your audience has not had a statistics class before?

ANOVA tells you if a set of features reduces the amount of unexplained information more by having the groupings than by leaving out all groupings.

A T-test is used to test differences between two means. For an example, the mean of the experiment group vs a control group. An ANOVA test, on the other hand, is indicated when there are three or more means or populations to be examined.

When only two samples are looked at, the T- test and ANOVA test will yield the same results.

Beyond two examples, the T – test can be used to evaluate other means using many T – test, but this method becomes unreliable and subject to increased error.

ANOVA or analysis of variance allows one to use statistics to test the differences between two or more means and decreases the probability for a type 1 error, which might occur when looking at multiple two-sample T – test. Therefore, ANOVA is indicated for testing hypotheses where there are multiple means or populations (Making Connections:The Two-Sample t-Test,Regression, and ANOVA).

The analysis of variance is carried out by the following: Population variance is estimated by variance among sample means. A second estimate of variance is made from variance within samples, comparing these two estimates of variance. If they are approximately equal in value, it is inferred that the means are not significantly different (Making Connections:The Two-Sample t-Test,Regression, and ANOVA).  

 

Reference:

Making Connections:The Two-Sample t-Test,Regression, and ANOVA. (n.d.). Retrieved March 18, 2015, from Pearson Highered: http://www.pearsonhighered.com/kuiper1einfo/assets/pdf/Kuiper_Ch02.pdf

 

 

 

comment faith

 

 I NEED A POSITIVE COMMENT BASED IN THIS ARGUMENT. BETWEEN 150-200 WORDS

 

As described by National Institute of Health, (2011), the mode, the median, and the mean are described to be the three measures of Central Tendency, or measures of center, or central location. Measure of central tendency aims to summarizes attempts to describing data as whole set, describing a single represented value of the middle, or its distribution. The characteristics of a population for which use of the mode, the median, and the mean is appropriate would be a retirement age population.

Mode is the most recurring value in the distribution. For example, a retiring group of 13 people with their ages ranges as follows; 58, 58,59,56,57,58, 57, 56, 56, 56, 56,56, 59 then the mode of this population distribution is 56, which is the most recurring number.

Median is the value appearing in the middle of the distribution in an ascending or descending order. With the same example of a retirement age population, the number in the middle of distribution is the median number, and in this case the number is 57. This is the most preferred value in the measure of central tendency when data is asymmetrical.

Mean is the average of the whole data set. This is a calculation of all values added together, and divided by the number of the observed values, for example; 58+ 58+59+56+57+58+ 57+ 56+ 56+ 56 +56+56+ 59=683 which is then divided by 11 observations which equals 62.09, or 62.1 years.

The time when it is inappropriate to use the characteristics of the measure of central tendency is when calculating the staff salaries, because the mean value may be skewed by the salary of those that earn large figures.

Reference

Luard Statistics, (2013). Measures of central tendency.

            Retrieved on 03/15/21017 from https://statistics.laerd.com/statistical-guides/measures-central-tendency-mean-mode-median-faqs.php

National Institute of Health, (2011). Measure of Central Tendency.

            Retrieved on 03/15/2017 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157145/

 

 

 
                                

 

When solving an IP (integer program) with LP relaxation rounding could result in

When solving an IP (integer program) with LP relaxation rounding could result in…
Answer 

An Infeasible solution.

A suboptimal solution.

An optimal solution.

All of the above.

 

 

 

 

 

A well-defined decision variable…
Answer 

Contains a min or max.

Contains a quantity, a noun, a verb, and a time period.

Is what is holding you back from your goal.

All of the above 

 

 

 

 

When making a mathematical model there is a tradeoff between how well it…
Answer 

Represents real world and how easy it is to solve.

Uses mathematical symbols and how well it represents reality.

Represents iconic models and analog models.

Communicates with computers and humans 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cintis Coal’s accounting manager has been tasked by the CEO to determine which mines the company should open in the next 5 years. He has worked with other departments to estimate the cost of opening each mine as well as the total expected return on investment over the next 15 years. The CEO wants to allocate only $2,000,000 over the next five years for opening the mines. The accounting manager needs to maximize the return while staying within the budget. The cost and return for each project is listed below.

Mine Cost (in $1000) Return (in $1000) 

1 $300 $600

2 $400 $1000

3 $450 $650

4 $600 $1200

5 $800 $1400

6 $1200 $2000

Let Xi = 1 if mine i is selected and 0 otherwise. i = 1,2,3,4,5,6

Max Return Z = 600 X1 + 1000 X2 + 650 X3 + 1200 X4 +1400 X5 + 2000 X6

St

300X1 +400 X2 + 450 X3 + 600 X4 + 800 X5 + 1200 X6 <= 2000

Xi = 0 or 1 for all i

The manager has determined that at most Cintis Coal wants to open 2 mines that do not return at least double the cost of opening the mine in the first 15 years. Write a constraint for this.
Answer 

X5 + X6 <= 2

X3 + X5 + X6 <= 1

X3 + X5 +X6 <= X1 + X2 + X4

X3 + X5 + X6 <= 2

 

Mine 5 can only be selected if mine 4 is selected and mine 6 can only be selected if mine 5 is not selected. Write two constraints for these.
Answer 

X4 <= X5 and X6 + X5 <= 1

X5 <= X4 and X6 – X5 <= 1

X5 <= X4 and X5 + X6 <= 1

X6 <= X5 and X4 + X5 <= 1

 

The $600 return on investment for mine 1 in this problem is a….
Answer 

Parameter

Constraint

Objective Function

Decision Variable 

 

 

 

 

Graph the following linear program to find the solution.

Let X = the number of hats to produce

Y = the number of shirts to produce

Max Profit Z = 3X+6Y

St. 7X+14Y>=14 (1)

4X+5Y<=20 (2)

X+Y <=7 (3)

X<=4 (4) 

X,Y>=0

How many extreme points are there in the feasible region? 
Answer 

5

6

4

3

Which constraints are redundant constraints?
Answer 

(3) and (4)

(4)

None are redundant

(3) 

 

What is the optimal number of hats and shirts to produce?
Answer 

Producing 4 hats and 0 shirts is optimal.

Producing 4 hats and 1 shirt is optimal.

Producing 2 hats and 0 shirts is optimal.

Producing 0 hats and 4 shirts is optimal. 

 

Which constraints are binding?
Answer 

(4)

(2) and (4)

(2)

(1)