R help - Sep 2015 - I need help with extracting data :(

So this is the question that I need help on. :(
4.) ?Warpbreaks? is a built-in dataset in R. Load it using the function
**data(warpbreaks)**. It consists of the number of warp breaks per loom,
where a loom corresponds to a fixed length of yarn. It has three variables
namely, breaks, wool, and tension.
a.)	Write a code (Hint: a logical expression) that extracts the observations
with wool type A and tension level M. Assign it to the object
**AM.warpbreaks**.
b.)	For the ?AM.warpbreaks? dataset, compute for the mean and the standard
deviation of the breaks variable for those observations with **breaks value
not exceeding 30**. 

My code for 4a) (However, it didn't work. Can somebody help me how to solve
this problem?) :(
>warpbreak <- data(warpbreaks("breaks", "wool",
"tension"))
>AM.warpbreaks <- c('','type A','level M')
Thanks! :)




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This is pretty clearly a homework question and this list does not do 
people's homework for them.

You need to learn more about the basics of R syntax.  Read "An 
Introduction to R", readily available from the R web site.

cheers,

Rolf Turner

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On 11/09/15 22:53, massmatics wrote:
> So this is the question that I need help on. :(
> 4.) ?Warpbreaks? is a built-in dataset in R. Load it using the function
> **data(warpbreaks)**. It consists of the number of warp breaks per loom,
> where a loom corresponds to a fixed length of yarn. It has three variables
> namely, breaks, wool, and tension.
> a.)	Write a code (Hint: a logical expression) that extracts the
observations
> with wool type A and tension level M. Assign it to the object
> **AM.warpbreaks**.
> b.)	For the ?AM.warpbreaks? dataset, compute for the mean and the standard
> deviation of the breaks variable for those observations with **breaks value
> not exceeding 30**.
>
> My code for 4a) (However, it didn't work. Can somebody help me how to
solve
> this problem?) :(
>> warpbreak <- data(warpbreaks("breaks", "wool",
"tension"))
>
>> AM.warpbreaks <- c('','type A','level M')