Difference between LaTeX classes and packages

Hi guys,

• The first thing to remember is that a document uses only one class, but it can use many packages. 
• That means that particular class we use in our document (e.g. myclass.cls) sets the overall format, like the structure of the sections and etc.
• A package, however, add more functionality to the document. For example tikz is a package which allows you to draw diagrams, but does not modify the document style at all.
• A class file can also be based on another "one" class and multiple packages.

To start Firefox in Safe mode

Hey guys,

To start Firefox in safe mode just hold the shift key while Firefox is starting.
That's all!

Cheers!!!

Import .eps files in GIMP fail

Hey,

Today I am going to tell you how to overcome the problem of importing .eps files in GIMP software.

• First, you have to have ghostscript (http://www.ghostscript.com/) installed in your system.
• After that you have to set the environment variable GS_PROG set to the path of your ghostscript .exe location
• to set the environment variable (Win7):
right click on My Computer -> Properties -> Advanced system settings -> Advanced tab -> Environment Variables
• In system variables -> New
• variable name : GS_PROG
• variable value: e.g. E:\Program Files\gs\gs9.04\bin\gswin32.exe (insert the ghostscript path appropriately)
• restart GIMP

LaTex \left and \right

Hi guys,

• Today I will tell you what \left and \right means in LaTex.
• Sometimes you need to enclose fractions in equations within tall brackets. That's where these \left and \right comes in to play.
• syntax: \left c1 cmds \right c2
c1 and c2 are called enclosing symbols. Some of the frequently used enclosing symbols are: (  )  [  ]   \{   \}  |

\left (\frac{a}{b} \right )

• If you didn't use \left and \right, this is what you will get:

          (\frac{a}{b})
               

• Sometimes you may need such a symbol, but only at one side.
• Then the syntax is: \left . cmds \right c2
• That is, a period is used for the side where you do not use the enclosing symbol

                \left . \frac{a}{b} \right |

               

                   

Standard deviation (SD), Standard error (SE) and Confidence Interval (CI)

Hi all,

I had a tough time understanding these 3 statistics and let me share what I understood with you guys.

• The first thing we should know is that we will always be dealing with samples from a large population. For example, say we want to know the average height of a Japanese woman. We will measure the height of n=100 Japanese women and we will draw some conclusions about the entire Japanese women population.
• Now, standard deviation (SD) of the 100 measurements will give us how our measurements vary around mean of the measurements.
• the standard error (SE) (of the mean) will tell us the variability of our computed mean. I repeat; SD gave the variability of data around the mean and SE gives the variability of the computed mean, not the data around it.
• finally, the confidence interval (CI) give us where the real mean of the large population might lie.


• Now, how do we compute these 3 values?
• SD is computed directly from our measurements.

• SE is computed from SD.

                    This is how you get it.

• if xi are n independent observations from a population that has a mean u, and standard deviation s then the variance of the total

is ns^2 (because for two it will be s1^2 + s2^2)

• The variance of T/n (mean) must be 1/n^2 * (ns^2) = s^2 / n
• Thus, the standard deviation of T/n = s/(sqrt(n))

• CIs are computed from the SE.
• Say, we need a 95% CI, then
• upper 95% limit =

• lower 95% limit =

1.96 comes from 0.975quantile of the normal distribution -- (100-95)/2%=0.975

writing strings in excel by MATLAB

Hey guys,


When you want to write some value in an excel file from MATLAB, you can use:

my_string = 'test';
xlswrite('my_excel.xls', {my_string}, 'my_page', 'A1');

where,
my_excel.xls: file I need to write
{my_string}: the content
{} of my_string makes sure the whole string is written in one cell.
my_page: the page of the escel file
A1: the cell

MS Excel: Get rid of rows that contain a particular string

Hey guys,

This is how it is done. We make use of macros to achieve this.

1. If the developer tab is not visible make it visible as follows: (MS Excel 2007)
1. Click the office button
2. Then, click the Excel Options button
3. Choose "Popular" tab
4. In "Top option for working with Excel", tick the "Show developer tab in the Ribbon"


2. Now go to the developer tab and click on the visual basic button.


3. Double click on the sheet1(sheet1)...or the sheet you want the macro to run


4. Now enter this code:

Sub DoIt()
    Dim Sentences
    Dim i As Long
    Dim iWordPos As Integer
    
    Sentences = Range("A1", Range("A65536").End(xlUp))
    lRow = 0
    For i = Range("A65536").End(xlUp).Row To 1 Step -1
        iWordPos = InStr(LCase(Sentences(i, 1)), LCase("MyString"))
        If iWordPos > 0 Then
            Range("A" & i).EntireRow.Delete shift:=xlShiftUp
        End If
    Next i
End Sub

'Comment : Range("A65536").End(xlUp) is the final cell

5. Replace MyString with the string you want to search