Thread: Sample Questions for final

Hello all!

My instructor gave us these questions for practice and I need to be walked through them because I am lost and need to be assisted once again to make sue I know what I am doing. Okay, here they are:

Problem A: To revise an existing inventory system, a company needs to know something about the lead time for orders it places for a critical part. The company looks at the last 20 orders placed and finds that the lead time in days are: 1,4,6,7,4,5,6,8,4,5,7,8,4,6,7,10,4,6,7,11.

a-What is the mean lead time for an order?

b-What is the median lead time for an order?

c-What is the mode lead time for an order?

d-What statistic or statistics do you think represents a typical lead time and why?



Prob. B A normal population has a mean of 20.0 and a standard deviation of 4.0.

a-Compute the z-value associated with 25.

b-Compute the z-value associated with 18.


Thanks for all your help!!

Originally Posted by foofergutierrez

Hello all!

My instructor gave us these questions for practice and I need to be walked through them because I am lost and need to be assisted once again to make sue I know what I am doing. Okay, here they are:

Problem A: To revise an existing inventory system, a company needs to know something about the lead time for orders it places for a critical part. The company looks at the last 20 orders placed and finds that the lead time in days are: 1,4,6,7,4,5,6,8,4,5,7,8,4,6,7,10,4,6,7,11.

a-What is the mean lead time for an order?

Mr F says: Add up the data. Divide the total by how many data there are.

b-What is the median lead time for an order?

Mr F says: Order the data from smallest to biggest:

1, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, ,7 ,7 ,7 8, 8, 10, 11.

Find the middle:

1, 4, 4, 4, 4, 4, 5, 5, 6, 6, | 6, 6, 7, ,7 ,7 ,7, 8, 8, 10, 11.

The median is 6.

c-What is the mode lead time for an order?

Mr F says: Apply the definition of the mode.

d-What statistic or statistics do you think represents a typical lead time and why?

Mr F says: Choose between mean, median and mode. Which one best represents a typical datum? Why?


Prob. B A normal population has a mean of 20.0 and a standard deviation of 4.0.

a-Compute the z-value associated with 25.

b-Compute the z-value associated with 18.

Mr F says: In both cases apply the usual formula , where is the mean and is the standard deviation:

a. .

Thanks for all your help!!

Don't you have examples in your class notes and/or textbook?

Mr. F,
To answer your question at the end of your response, we do not have specific examples since the class is online and the books are e-text it is difficult to determine what is right and wrong. By the way, are you criticizing me for asking obvious questions? I just want to make sure that I have it down right so I do not screw up on the final questions that he is going to ask us so if you don't want to help, ignore my post and move onto to someone else. Thanks for your help anyways and maybe I will go elsewhere to get help that I need.

Originally Posted by foofergutierrez

Mr. F,
To answer your question at the end of your response, we do not have specific examples since the class is online and the books are e-text it is difficult to determine what is right and wrong. By the way, are you criticizing me for asking obvious questions? I just want to make sure that I have it down right so I do not screw up on the final questions that he is going to ask us so if you don't want to help, ignore my post and move onto to someone else. Thanks for your help anyways and maybe I will go elsewhere to get help that I need.

For the record, the question I asked was a genuine one and is always the question I ask when questions very similar to the sort of examples one would expect to find in class notes and textbooks are asked.

I'm sorry that both the question I asked and the help I provided were, respectively, so antagonistic and so unhelpful that you would seek to discredit me by suggesting that you'll go elsewhere for help because of my post.

One last thing - I'd suggest you vent more of your spleen towards the folk who run your on-line course .....

Regards and good luck with your studies.

I chose to take online classes due to my lifestyle and I expected to have issues but not like the ones I am facing in this class. I did not mean to sound ungrateful for the help that you did provide but the way you asked it was like "Did you even bother to look in the book?". I joined this math help forum to get help and learn from mistakes that I am making but it felt as if you are critizing me for even asking. I do indeed appreciate the help and assistance I receive from the people in the forum so don't get me wrong when I get offended by what I feel is a question that should not be asked. I am truly sorry for offending you as well. I hope you will be able to help me on future questions that I may have and that will be soon since I am start the second part to ths class next week.

So what is stopping you from ordering yourself a decent stats books off amazon?

Originally Posted by bobak

So what is stopping you from ordering yourself a decent stats books off amazon?

Well, money can be tight sometimes. IMHO these on-line courses have a legal and moral obligation to provide decent material to their on-line students. IMHO some on-line courses treat their students in a most reprehensible manner and should be held to greater account.

How are these online courses weighted against traditional math courses?

Originally Posted by bobak

So what is stopping you from ordering yourself a decent stats books off amazon?

Bobak, Do you have a family of your own? Money is tight when you have 4 children and a husband, a mortgage and gas prices are through the roof. Believe me, if I could I would order the books I need to understand Statistics but having gas to get to and from work and paying daycare is a higher on my priority list. The books that I do pay for are okay to an extent but they do not provide the extra help that many students such as myself, may need. All I am trying to do is better myself to better the lives of my children and my spouse. Doesn't anyone understand that? Maybe if you were in my situation you would understand and get off my back.

Originally Posted by bobak

How are these online courses weighted against traditional math courses?

I think that the courses online are just as effective in teaching students the basics in Math and Algebra but when Statistics comes into play, it is a bit more difficult to comprehend since you do not get the one on one or visual help that you may need. I have been an online student for about 2 1/2 years and this is by far the most difficult class that I have had yet, my GPA is going to drop big time because of this one course. Thankfully I only have maybe a year left until I obtain my Bachelors degree.

Originally Posted by foofergutierrez

Bobak, Do you have a family of your own? Money is tight when you have 4 children and a husband, a mortgage and gas prices are through the roof. Believe me, if I could I would order the books I need to understand Statistics but having gas to get to and from work and paying daycare is a higher on my priority list. The books that I do pay for are okay to an extent but they do not provide the extra help that many students such as myself, may need. All I am trying to do is better myself to better the lives of my children and my spouse. Doesn't anyone understand that? Maybe if you were in my situation you would understand and get off my back.

You're obviously having a tough time of it right now. But Bobak is probably young enough not to have these worries. And until you have these sorts of worries, they probably don't come to mind readily. I'm sure Bobak's post meant well. Unfortunately, sometimes things are said that mean well but probably cut close to the bone ......

So here's something else that means well and, I hope, doesn't cut too close to the bone ......

Does your on-line enrolment give you access to a library that has textbooks likely to be useful to you? If so, can you easily get to that library? If so, are you able to borrow those books for longer than just overnight (a week perhaps. Or a month)? Do you have any contacts that have access to such textbooks?

There is an online library but it does not have text books that we can use. It is more of reference materials than anything else. As for borrowing some books, I work during the day during the week so it is hard for me to get to a library to see if I can borrow books and another thing is that they do not let you borrow books that are considered reference.
I really do not know how I am going to make it through the second half of this class because it requires a lot of time and dedication which I am unable to provide at this time. I am truly thinking of quiting school all together but then I know I will regret it in the long run. Thanks for the help you are trying to give me and believe me, I really do appreciate it.

Originally Posted by foofergutierrez

There is an online library but it does not have text books that we can use. It is more of reference materials than anything else. As for borrowing some books, I work during the day during the week so it is hard for me to get to a library to see if I can borrow books and another thing is that they do not let you borrow books that are considered reference.
I really do not know how I am going to make it through the second half of this class because it requires a lot of time and dedication which I am unable to provide at this time. I am truly thinking of quiting school all together but then I know I will regret it in the long run. Thanks for the help you are trying to give me and believe me, I really do appreciate it.

Now that the circumstances of your studies are known, the replies you get to your questions may well go the 'extra yard' to help you out.

Hey everyone who helped me in Feb. I am back for the second part of my class in Statistics and I know I am going to need help. Beleive me when I say that I am very grateful for all of you who help me and do not judge me for questions that I may ask because as they may come simple for you they may not for me. So, thank you in advance and I look forward to your help!!