Why learn Statistics?
2014 Salary Guides from Robert Half Technology and The Creative Group presents us with some exciting data for the “Data Scientists”, if you look carefully. IT professionals with high level of skills in big data manipulation are all set to likely get a minimum of 5% salary boost. The top six jobs in the IT industry with biggest percentage raise from last year are presented in the table below. Although the value of data analysis skills may not be apparent for some of the positions listed below, it really plays a big role in their respective jobs.
We all know that year 2013 is named the year of the big data already.
Statistics is the tool that you need to look and present the data in a form that others could understand and appreciate. Just as an example, I am going to use R and prepare some code to present the tabular data in various graphical forms.
|Mobile applications developer||$100,000||$144,000||7.8|
|Business intelligence analyst||$101,250||$142,250||7.4|
|Information systems security manager||$115,250||$160,000||6.8|
|User experience designer||$78,000||$120,000||7.5|
|User experience specialist||$79,000||$118,000||5.9|
First, you need to create a csv file with the data. salary csv file
# Read the CSV File into a data-frame
3. Check the data-frame structure:
‘data.frame’: 6 obs. of 4 variables:
$ Jobs : chr “Mobile applications developer” “Business intelligence analyst” “Information systems security manager” “User experience designer” …
$ Min : int 100000 101250 115250 78000 66000 79000
$ Max : int 144000 142250 160000 120000 103000 118000
$ percent_increase: num 7.8 7.4 6.8 7.5 6.3 5.9
4:Do the Summary command:
Jobs Min Max percent_increase
Length:6 Min. : 66000 Min. :103000 Min. :5.900
Class :character 1st Qu.: 78250 1st Qu.:118500 1st Qu.:6.425
Mode :character Median : 89500 Median :131125 Median :7.100
Mean : 89917 Mean :131208 Mean :6.950
3rd Qu.:100938 3rd Qu.:143563 3rd Qu.:7.475
Max. :115250 Max. :160000 Max. :7.800
5. Find median values:
Min Max percent_increase
89500.0 131125.0 7.1
from the statistics, it can be concluded that the minimum salary median is 89,500 usd and the median of the maximum salary is 131,125 usd.
6. Graphical presentation of the data:
Let’s do pie chart for the minimum salary for the top 6 groups:
6. Other types of graphs? What about a barplot?
#Rainfall stackplot code in R
#Update the csv file to update new graph.
#coded on 2/10/2014
#Code by Ankan Basu, CPG, Hydrogeologist
# Read the CSV File into a dataframe
#check structure of the selected vector data
#Assign screen design / graphs per page
#Assign empty space around the graphs
#to draw legen outside the axis, use the following command.
par(xpd = T)
### By itself, changing the top margin does not help.
### It is also vital to set the xpd parameter to T so that
### R will draw outside the main plot region
#xaxt = “n”, # this removes default x-axis labels.
las=2, # use to make the xaxis labels vertical,