# Please help - probability question

#### ElleWoods69

##### New member
I am a grad student who has to take this online course to complete my masters but am so lost and desperately need help on my homework. I truly don't understand what to do despite reading and re-reading the chapter and googling for help.

The time required to assemble an electronic component is normally distributed with a mean and a standard deviation of 29 minutes and 14 minutes, respectively.

a. Find the probability that a randomly picked assembly takes between 20 and 34 minutes. (Round "z" value to 2 decimal places and final answer to 4 decimal places.)

b. It is unusual for the assembly time to be above 47 minutes or below 14 minutes. What proportion of assembly times fall in these unusual categories?

#### Subhotosh Khan

##### Super Moderator
Staff member
I am a grad student who has to take this online course to complete my masters but am so lost and desperately need help on my homework. I truly don't understand what to do despite reading and re-reading the chapter and googling for help.

The time required to assemble an electronic component is normally distributed with a mean and a standard deviation of 29 minutes and 14 minutes, respectively.

a. Find the probability that a randomly picked assembly takes between 20 and 34 minutes. (Round "z" value to 2 decimal places and final answer to 4 decimal places.)

b. It is unusual for the assembly time to be above 47 minutes or below 14 minutes. What proportion of assembly times fall in these unusual categories?
Do you have access to z-table?

#### LCKurtz

##### Full Member
Do you know how to use tables for the standard $$\displaystyle n(0,1)$$ distribution? Do you know how to use $$\displaystyle z = \frac {x-\mu}{\sigma}$$?

#### Harry_the_cat

##### Senior Member
Can you represent the question on a diagram?

#### ElleWoods69

##### New member
Do you have access to z-table?
No and I don't even know what that is!

#### ElleWoods69

##### New member
Can you represent the question on a diagram?
No, I just have to enter a number
Do you know how to use tables for the standard $$\displaystyle n(0,1)$$ distribution? Do you know how to use $$\displaystyle z = \frac {x-\mu}{\sigma}$$?
No I do not. I haven't taken a math course in 6 years and am completely lost after days of trying to figure it out with my textbook.

#### Jomo

##### Elite Member
You will not be able to do this problem easily without a z-table.

#### ElleWoods69

##### New member
You will not be able to do this problem easily without a z-table.
Then is anyone able to give me an answer for that question since I don't have a z-table? I will have to try to get additional help but can't get a tutor right now obviously.

#### Jomo

##### Elite Member
Sorry, but we do not give answers to students as this is a math help forum. We prefer that the student solves their own problems with help from the helpers on this forum.

I assure you that if you do a google search for z-tables you will find 100's of z-tables.

#### ElleWoods69

##### New member
Sorry, but we do not give answers to students as this is a math help forum. We prefer that the student solves their own problems with help from the helpers on this forum.

I assure you that if you do a google search for z-tables you will find 100's of z-tables.

#### Jomo

##### Elite Member
Then is anyone able to give me an answer for that question since I don't have a z-table? I will have to try to get additional help but can't get a tutor right now obviously.
There are 1000's of online tutors available to help you right now. If you message me I can give you list of some.

#### Subhotosh Khan

##### Super Moderator
Staff member
There are 1000's of online tutors available to help you right now. If you message me I can give you list of some.
Ofcourse - you'd have to pay for those services......

#### LCKurtz

##### Full Member
Just do a Google search for calculating probabilities with a normal distribution. You will find lots of free youtube videos. It isn't rocket science and since you are a graduate student in something, you shouldn't have any trouble.

#### Subhotosh Khan

##### Super Moderator
Staff member
I am a grad student who has to take this online course to complete my masters but am so lost and desperately need help on my homework. I truly don't understand what to do despite reading and re-reading the chapter and googling for help.

The time required to assemble an electronic component is normally distributed with a mean and a standard deviation of 29 minutes and 14 minutes, respectively.

a. Find the probability that a randomly picked assembly takes between 20 and 34 minutes. (Round "z" value to 2 decimal places and final answer to 4 decimal places.)

b. It is unusual for the assembly time to be above 47 minutes or below 14 minutes. What proportion of assembly times fall in these unusual categories?
Have you resolved your question posted in:

#### Harry_the_cat

##### Senior Member
Can you use a calculator for this? If so, what calculator do you have?

#### Harry_the_cat

##### Senior Member
No, I just have to enter a number
OK so you just have to enter the answer. But do you know how to represent this on a diagram?