Lecture # 8 Spreadsheets II: Numeric Functions and Data Management

Lecture # 8Spreadsheets II:

Numeric Functions and Data Management

TodayQuestions: From notes/reading/life?

Cool spreadsheet functions you discovered?

1. Introduce: Can spreadsheets help with my credit problems?

2. Explain: Numeric Functions: Logical Functions, Branching

Data Management: Indexing, Look-Up, Charts

3. Demo: Spreadsheet Magic – follow along on laptop

4. Practice: Your Group solves a problem with a spreadsheet

5. Evaluate: Share and evaluate your solution• Re-practice: Calculate monthly payments with a spreadsheet

Understand: What is the “Program” or Algorithm behind the

Scenes that makes the function work?

Do Homework # 3

Spreadsheet Numeric Functions

Functions

Simple functions

• Array functions

• IF - logical functions

Function notation

• A function is a piece of computation that takes 1 or more arguments (data) and returns a value

• Function( arg1, arg2, arg3 )– Sine(90)– Max(100,200,120,-7)– Sqrt( min(7+4, 9) )

Using functions

Finding functions

Functions

• Simple functions

Array functions

• IF - logical functions

Average

Other array functions

• Min

• Max

• Stdev - standard deviation

• Median

• Product - multiply them all together

Functions

• Simple functions

• Array functions

IF - logical functions

If – Logical Functions and Branching

• If ( test, trueVal, falseVal)

IF with AND

Review

• Functions - name with arguments– Finding functions

• Array functions– Sum(B6:D32)– Average(F14:R75)

• IF - AND - OR











Do Homework # 3

Spreadsheet Data Management

Data management

• Index/Lookup functions

• Sorting

• Charts

Index Demo











Do Homework # 3

Group Exercise: What Day were You Born?

• Using the functions Index and Weekday, discover which day (Sunday – Saturday) you were born.

• Do this for each member of your group.

• Which day of the week did the 9/11/2001 attack occur?

• You have 10 minutes

Index function

• DayNames = Sheet[C2:C8]• DayNumber = WEEKDAY(B2)• Sheet[B3] = DayNames[DayNumber,1]

Match function

Match Demo

Lookup Function

Lookup Function

How much time? 5, 50, 50000

Lookup Demo

Sorting

Ascending - smallest to largest

item[i]<=item[i+1]

Descending - largest to smallest

item[i]>=item[i+1]

Sort Demo

• Simple sort buttons

• Sort menu item– Data -> Sort

• Ward list– Name, apartment, dates last month

Charts











Do Homework # 3

Homework #3: What is Your Payment?

• You want to buy a car for $10,000 and you want to pay it off in 3 years. You can get a loan for 4%

annual interest. Use a spreadsheet function to calculate your monthly payment.

• Let’s say that the maximum monthly payment you can afford is $200 a month. How long will it take you to pay off the car?

• Let’s say you are stuck with 4% annual interest and 3 years. How expensive of a car can you afford?











Do Homework # 3

Spreadsheet “Programs”

• What is the “Program” behind the scenes

that makes a spreadsheet function work?

Sum program

Sum=0;

for (each row R)

{ for (each column C in row R)

{ Sum=Sum+Sheet[R, C]; }

}

Sum 0R ?C ?

Sum 0R 1C ?

Sum program

Sum=0;

for (each row R)



}

Sum program

Sum=0;

for (each row R)



}

Sum 0R 1C A

Sum 23R 1C A

Sum program

Sum=0;

for (each row R)



}

Sum 23R 1C B

Sum program

Sum=0;

for (each row R)



}

Sum 47R 1C B

Sum program

Sum=0;

for (each row R)



}

Sum 47R 2C B

Sum program

Sum=0;

for (each row R)



}

Sum -31R 2C A

Sum program

Sum=0;

for (each row R)



}

Sum -31R 2C B

Sum program

Sum=0;

for (each row R)



}

Sum 1213R 2C B

Sum program

Sum=0;

for (each row R)



}

Sum 1213R 3C B

Sum program

Sum=0;

for (each row R)



}

Sum 1213R 3C A

Sum program

Sum=0;

for (each row R)



}

Sum 1236R 3C A

Sum program

Sum=0;

for (each row R)



}

Sum 1236R 3C B

Sum program

Sum=0;

for (each row R)



}

Sum 1256R 3C B

Sum program

Sum=0;

for (each row R)



}

Count programCount=0;

for (each row R)

{

for (each column C in row R)

{

Count=Count+1;

}

}

Average programSum=0;Count = 0;for (each row R)

{ for (each column C in row R) { Sum=Sum+Sheet[R,C];

Count = Count+1;}

}Average = Sum/Count;

Match algorithm

DayNames = Sheet[C2:C8];

for (i=0; i<sizeof(DayNames); i=i+1)

{

if (DayNames[i] == Sheet[B3]) return i+1;

}

What is the average time to do this function?N = 50?N=50000?

Spreadsheets

• Spreadsheet is an array of values and expressions• Reevaluate every expression for every change• Number overflow/underflow• Functions - name(arg1, arg2, arg3)• Array functions - sum, average, count• Data functions - match, vlookup• Sorting• Charts

Lecture # 8 Spreadsheets II: Numeric Functions and Data Management

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