## Boxplot

##### Boxplot’s relation to Mean
• Longer tail on the upper side means mean is higher than the median (median is shifted towards LQ) [a +vely skewed distribution]
• Longer tail on the lower side means mean is lower than the median (median is shifted towards UQ) [a -vely skewed distribution]

## Minitab Tricks

### Importing .dat, .csv, xls file in Minitab

• File -> Open Worksheet  [Choose .dat, .csv etc]

### Removing empty cells in boxplot for between-subject design

• Double click the axis variable.
• Uncheck: “Include empty cells”.
• This shows only those ticks that has some data in it, which is very useful in case of between-subject design, as the participants are divided into different treatment groups.

### Changing order of x-axis groups

Minitab picks a default ordering for x-axis groups (usually Alphabetical or Numeric ordering) If you want to change the order of group variables on x-axis (e.g.  Low, Medium, High to Medium, Low, High):

• Select the column in the data window which represents the group in the graph.
• Right click and select Column->Value Order
• Select User-specified order
• Add the desired order, Click OK
• Any graph from now onward will follow that order

### Changing color of x-axis groups

• The colors for groups can be selected in the dialog box at Tools->Options->Graphics-> Data View With Groups -> Symbol and Line Colors
• You can also change color for individual groups or sub-groups by double clicking on the bars and choosing appropriate attributes in the dialog box.
• Before double clicking, click just once to switch between different grouping variables.

## SEM vs 95% CI

##### Notes:
1. Assuming unpaired t-test.
2. SEM bars are often about half or less smaller than 95% CI bars.
3. SEM Bars
• When SEM bars overlap , There is surely no statistical significant difference (p>0.05).
• When SEM bars do not overlap, There may or may not be a statistical significant difference.
4. 95% CI bars
• When CI bars overlap, There may or may not be a statistical significant difference.
• When CI bars do not overlap, There is definitely a statistical significant difference (p<0.05).

## Letter size paper in pdflatex

Sometimes problem comes from incorrect specification of PDF page height and width.

Put this code after \begin{document}
\special{papersize=8.5in,11in}
\setlength{\pdfpageheight}{\paperheight}
\setlength{\pdfpagewidth}{\paperwidth}
% \hoffset = -0.2truein  %moves everything left and right
% \voffset = -0.2truein  %moves everything up and down