Session3 Lecture Materials
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Transcript of Session3 Lecture Materials
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Session 3
Data Summarization
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XPOVERVIEW
2
Descriptive Statistics in Excel
Excel Tables: a simple case
Pivot Tables
Experiments/exercise with Pivot Tables
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Summarizing Numerical Data: Descriptive Statistics
Characteristic Interpretation
Central Tendency Where are the data values concentrated?
What seem to be typical or middle data value?
Dispersion How much variation is there in the data?
Are there unusual values?
Shape Are the data values distributed symmetrically
or Skewed? Sharply peaked or Flat?
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XPDescriptive statistics in Excel
4
Use Data Analysis tool box
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XPWhat is a Table
5
Table is a rectangular range of structured data
Each row contain information about an entity, say a
customer or country
Each column contain information on an attribute of the
entities described.
Typically Table header display information about a column
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XPWhy Table?
6
When a range is designated as a Table, Excel acts
intelligently as to the actions performed with it. A new row or column added is automatically added to the table
A chart created with the Table automatically accommodates a new row
Each column header in a table allows sorting and filtering
Clicking displays various facilities
Calculated columns formula in a column is automatically
propagated
Structured References Eg. AVERAGE(Salary[Basic])
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XPCreating an Excel Table
7
Click the Insert tab on the ribbon, and then click the
Table button
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XPSorting Data
8
You can sort the records in a table
Sorting Multiple Columns: Use Custom Sort Dialog Box
Specify the primary sort field, sort on type and the sort order
Click Add Level and continue
Sorting Using a Custom List in Custom Sort Dialog Box
Select Custom List in sort order
In the List entries box, type each entry for the custom list
in a separate line and click Add
https://www.youtube.com/watch?v=KS9N4yAjuYQ
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XPTotal Row: Calculate Summary Statistics
9
Used to calculate summary statistics for the columns in an
Excel table
Contextual Menu: Table Style Options Group: Total Row
option
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XPBack water investments needs your help
10
You are a manager at Backwater investments(BI)
BI makes money by obscure investments in developing
markets
They pick investment opportunities that may not be
clearly visible for others to pursue
To do this BI depends heavily on the expertise of their
analysts who have impeccable judgment and good
connections to get information
Your job is to consult these analysts and combine their
expert opinions to make good investment decisions
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XPThe analysts are having a fight
11
Currently BI has 20 analysts
You find that these Analysts are having big disagreements over
a number of current geopolitical trends
BI is unable to make in investment decision now because there
are a bunch of different issues over which the analysts are
fighting over
To resolve the issue we need to find out
Where precisely are the disagreements?
Is there any consensus among any issues?
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XPBI boss has asked you to help!
12
What can you do?
First find out the issues over which the analysts are fighting
It seems there are six areas over which they have different opinions. They
are
1. Will Russia subsidize oil in next quarter?
2. Will Russia purchase EuroAir?
3. Will Vietnam decrease taxes this year?
4. Will Vietnam's government encourage foreign investments this year?
5. Will Indonesian tourism increase this year?
6. Will the Indonesian government invest in ecotourism?
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XPSubjective probabilities can help
13
This is a numerical measure one can assign to his/her belief in
something
What about asking all of them to provide subjective
probabilities on the SIX issues?
Let them give a percentage value
Hope all will agree
All have responded
Let us see the thinksheet
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XPExpert Statement 1 Statement 2 Statement 3 Statement 4 Statement 5 Statement 6
1 87% 68% 37% 39% 5% 77%
2 88% 40% 11% 56% 28% 81%
3 89% 47% 67% 33% 0% 85%
4 91% 88% 7% 38% 24% 78%
5 91% 37% 8% 19% 0% 72%
6 92% 60% 30% 19% 18% 84%
7 87% 47% 66% 27% 5% 88%
8 92% 46% 41% 33% 3% 69%
9 88% 59% 83% 14% 12% 74%
10 92% 23% 9% 30% 9% 91%
11 88% 34% 0% 58% 2% 92%
12 89% 78% 46% 28% 5% 70%
13 92% 70% 45% 33% 1% 3%
14 88% 80% 35% 35% 13% 81%
15 89% 54% 15% 16% 5% 87%
16 90% 67% 63% 19% 3% 70%
17 92% 74% 14% 33% 0% 79%
18 91% 21% 22% 40% 7% 89%
19 89% 21% 42% 28% 6% 81%
20 91% 36% 87% 27% 5% 84%
SD 2% 20% 26% 12% 8% 19%
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XPThey Agree on certain things: Boss is happy
Statement No Statement SD Agree/Disagree?
3 Vietnam will decrease taxes this year 26% Disagree
2 Russia will purchase EuroAir 20% Disagree
6Indonesian government will invest in ecotourism? 19% Disagree
4Vietnam's government will encourage foreign investments this year 12% Some what
5 Indonesian tourism will increase this year 8% Not much
1 Russia will subsidize oil in next quarter 2% Agree
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XPAnalyzing Data with PivotTables
16
A PivotTable is a dynamic/interactive table that enables you
to group and summarize either a range of data, an Excel table
or data from an external source into a concise, tabular format
for easier reporting and analysis
General purpose:
Quickly summarize data from a worksheet or from an external
source
Calculate totals, averages, counts, etc. based on any numeric
fields in your table
Can generate charts from your pivot tables
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17
Planning and Designing a PivotTable Report
Guidelines to create a PivotTable:
Review the source data
Determine the purpose of the PivotTable and write down the names of the fields you want to include
Determine which field contains the data you want to summarize and which summary function you want to use
Decide how you want to arrange the data
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XPPivot Table Advantages
18
Interactive: easily rearrange them by moving, adding, or
deleting fields
Dynamic: results are automatically recalculated whenever
fields are added or dropped
Easy to update: refreshable if the original worksheet
data changes
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XPMicrochip Manufacturer Example
19
You are the Financial Manager in a Microchip manufacturing
company
The company produces three types of chips viz; Chip 1, Chip 2
and Chip 3
The monthly sales data for all these chips in Canada, France
and United States are given
This shows Budget(Target), Revenue(Actual) and
Var(Difference between target and actual)
Data Set: Ptableexampletemplate.xlsx worksheet P1
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XPCreating a PivotTable
20
Excel table or data range for creating PivotTable
Verify the reference in the Table/Range box
Drag fields to the appropriate box in the layout section
Change the summary function, if needed
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XPCreating a PivotTable
21
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XPLet us see how much we are off/above the Target in
each Country, for each product
22
Move Var to Values
Move Product to Row Label
Move Country to Column Label
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XPAdding a Report Filter to PivotTable
23
Filter allows you to filter the PivotTable summary based
on one more fields
Filtering a field lets you focus on a subset of items in that
field
Homework: Find out how Slicers are used in excel
2013
https://www.youtube.com/watch?v=aRX2yO457vg
(starts at 9m 47s)
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XPHow much we are off/above the target in each country,
for each product, month by month
24
Move Var to Values
Move Product to Row Label
Move Country to Column Label
Move Month to Report Filter
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25
Changing a PivotTables Summary Function
A PivotTables summary function controls what type of
calculation is applied to the table data
Unless you specify otherwise, Excel applies the SUM function to
numeric data and the COUNT function to data fields containing
text
To change summary function use the Field Setting option in Pivot
Table tools.
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XPFor each month and each combination of country and product
we would like to see what percentage of actual sales made in
each month
26
Move Month to Row Label
Move Country to Report Filter
Move Product to Report Filter
Move Revenue to Values
Select Field Settings in PivotTable tools
Change name to Percentage of Actual
Show value as percentage of column
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XPCalculated Field calculating a new field from other fields
27
Show difference in each month as a percentage of target sales
We need to create a calculated field
PivotTable Tools: Fields, Items, & Sets: Calculated Field
Define a Name for the Field Percentage Not Achieved
Write the Formula =Var/Budget
Change Number Format to Percentage
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XPGrouping PivotTable Items
28
When a field contains numbers, dates, or times, you can
combine items in the rows of a PivotTable into groups
Select the items to group, right Click and Group
Change Group Name by Double Clicking the cell
Toggle between Detailed and Grouped display by clicking
the + or sign left to the group
https://www.youtube.com/watch?v=PiM6lxQi0iA
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XPRefreshing a PivotTable
29
You cannot change the data directly in the PivotTable.
Instead, you must edit the Excel table, and then refresh
the PivotTable to reflect the current state
Use GETPIVOTDATA Function when you want to reference a PivotTable cell value
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XPCreating a PivotChart
30
A PivotChart is a graphical representation of the data in
a PivotTable
A PivotChart allows you to interactively add, remove,
filter, and refresh data fields in the PivotChart similar to
working with a PivotTable
Click any cell in the PivotTable, then, in the Tools group
on the PivotTable Tools Options tab, click the
PivotChart button
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XPTips to note:
31
Double Click an item in the pivot table to Drill Down to the Details
Change the Data Source by selecting Change data source in Data Group in
Pivot Table Tools.
Better make Table and then Pivot Table because extending the source is
taken care of (if built from a Table ) on a refresh operation.
If it is built from a range, first we need to change the data source and
refresh.
In Pivot table options set refresh on opening (data tab), if needed