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spreadsheet Data and Spreadsheet Data and Spreadsheets  What are

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					Data and Spreadsheet
Data and Spreadsheets
 What are data?
 What are statistics?
 What are spreadsheets?
 How can you analyze data with
  spreadsheets?
Data
 Data are pieces of information that can define
  subjects
 Data can be numbers, words, descriptions
 The word data is PLURAL, datum is singular
 Example of Data about George:
      •   Age: 57.2 (years)
      •   43rd President
      •   Male
      •   Favorite letter: W
      •   Favorite words: Bring them on.
Types of Data
 Numbers – two types
   – Real #s – rational numbers – 57 years
   – Integers – whole numbers – 170 lbs
 Letters – called characters in programming
   – W is a character
 Words – called strings in programming
   – “Bring them on” is a strings, can be individual words or
     phrases
 Other : Image, Sound…
Statistics and Data
 Test Scores:        What statistics can you
   – Jeff: 88          calculate to describe
   – Mollie: 92        these data?
   – Marcie: 88
   – Dave: 47           – Try to think of four
   – Karim: 99            things to describe the
   – Willoughby: 6        data
   – Benjamin: 0      stop
Statistics
 Statistics are derived from the data
 Statistics are descriptions of data
 Statistics are meant to simplify the data
 Statistics can be misleading
Typical Statistics
 Sample Size - number of individuals measured = n

 Sum = S
 Average or Mean = S/n
 Median
   – Value of 50th percentile, half of values fall above, half below
 Maximum, Minimum, Range (Max-Min)
 Mode - most common value
 Standard deviation
               2
 Variance (SD )
Analyze these data...
 Mean, max, min,     sample size (n)
  range, median, mode  Mode
      • 18
      • 33
                       Sum S
     •   4
     •   47
                      mean=average=S/n
     •   49
     •   38           median = halfway
     •   29           Variance =S(x-mean)2/n
     •   4
     •   55
Calculators Compared with
Spreadsheets
   Calculators           Spreadsheets
Single Calculation    Many Interrelated
                      Calculations at Once
Built-in Math         Built-in and customized
Operators             Math Operation

Complex Calculations: Change a Value: Repeat
One Step at a Time    the Calculations you
                      Defined
Spreadsheets
 Spreadsheets are tables
               CostaRica Nicaragua
 Rainforest       625,000 3,712,000
 Dry Forest        50,000   300,000
 Total             675,000     4,012,000

 Spreadsheets allow calculations and
  manipulations of data
     • Calculations: mean, standard deviation
     • Manipulations: sort,
     • Visualizations: plot, pie chart
Spreadsheet Design Questions
 What numbers are you starting with?
 What numbers do you need to calculate?
 What are the relationships among the
  numbers to perform these calculations?
 What text do you need to make the
  spreadsheet clear to yourself and other
  people?
 Make a data table:
 Fly 1, length 13.4 mm, velocity 27 Kph, age 21 days
 Fly 2, length 9.4 mm, velocity 0 Kph, age 220 days
 Fly 3, length 9.3 mm, velocity 44 Kph, age 1 days
 Fly 4, length 13.4 mm, velocity 17 Kph, age 32 days
 Fly 5, length 17.4 mm, velocity 33 Kph, age 11 days

 How many columns?
 How many rows?
 #s go down or across?
Data Table
Fly #   Length   Velocity   Age

1

2

3

4

5
Microsoft Excel
 Typical spreadsheet program
  – VisiCalc is original commercial spreadsheet
  – Lotus 1-2-3 took over in the 1980s.
 Has similar controls to MS Word
 Now allows graphing (charts)
 Excel tables and graphs can be copied into
  MS Word
Excel Basic
 Data are stored in cells.
 Cells are name by Letters and numbers e.g.
  A12. This is also called cell reference.
 Cells can hold number, text, image, and
  most important thing: Formula.
 Formulas are started with a “=” sign. It can
  be any mathematical operations.
Relative Cell Reference
Absolute Cell reference
Friday’s Assignment
 We will work with Microsoft Excel to
  analyze some data
 Groups of two will submit one finished
  spreadsheet for the assignment

				
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posted:1/23/2012
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