A. Ruiz Méthodes d ’aide à la décision en RO Using Spreadsheets in Management Science Models Spreadsheets have become a powerful tool in management science modeling. Several reasons for the popularity of spreadsheets: –Data are submitted to the modeler in spreadsheets –Data can be analyzed easily using statistical and mathematical tools readily available in the spreadsheet. –Data and information can easily be displayed using graphical tools.

A. Ruiz Méthodes d ’aide à la décision en RO Basic Excel functions and operators Arithmetic Operations –Addition of cells A1and B1: –Subtracting cell B1 from A1: –Multiplication of cell A1 by B1: –Division of cell A1 by B1: –Cell A1 raised to the power in cell B1: = A1 + B1 = A1 - B1 = A1 * B1 = A1 / B1 = A1^ B1

A. Ruiz Méthodes d ’aide à la décision en RO Relative and absolute addresses –All row and column references are considered relative unless preceded by a “$” sign –When copied, ‘relative addresses’ change relative to the original cell position. Example: Cell E5 Cell G9 = A1+B$3+$C4+$D$6 = C5+D$3+$C8+$D$6 Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO The F4 key –Pressing F4 will automatically put a $ sign in highlighted portions of formulas. Press the F4 key once: The sign “$” appears in front of all rows and columns of the highlighted area of the formula. Press the F4 key twice: The “$” sign appears in front of only the row references of the highlighted area of the formula. Press the F4 key third time: The “$” sign appears in front of only the column references of the highlighted area of the formula. Press the F4 key forth time: All the “$” signs are eliminated. Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Arithmetic functions –Sum=SUM(A1:A3) Returns the sum A1+A2+A3 –Average=Average(A1:A3) Returns the arithmetic average of cells A1, A2, A3 –SUMPRODUCT =SUMPRODUCT(A1:A3,B1:B3) Returns the sum of products A1  B1+A2  B2+A3  B3 –ABS=ABS(A3) Returns the absolute value of the entry in cell A3. Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Arithmetic functions – continued –SQRT=SQRT(A3) Returns  A3 –MAX=MAX(A1:A9) Returns the Maximum of the entries in cells A1 through A9. –MIN=MIN(A1:A9) Returns the Minimum of the entries in cells A1 through A9. Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Statistical functions –RAND() =RAND() Generate a random number between 0 and 1 from a uniform distribution. –Probabilities and variable values under the normal distribution NORMDISTNORMINV =NORMDIST(25,20,3,TRUE)=NORMINV(.55,20,3) Returns P(X<25) when  = 20Returns x 0,, such that P(X<x 0 )=.55 and  = 3 when  = 20 and  = 3 NORMSDISTNORMSMINV =NORMSDIST(1.78)=NORMSINV(.55) Returns P(Z<1.78)Returns z 0, such that P(Z<z 0 )=.55 Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Statistical functions –Probabilities and variable values under the t- distribution TDISTTINV =TDIST(1.5,12,1)=TINV(.05,15) Returns P(t>1.5) Returns t 0,, such that when =12 P(t t 0 )=.025 when =15. Note: =TDIST(1.5,12,2) returns P(t 1.5) when =12. Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Statistical functions – Other probability distributions –Poisson =POISSON(7,5,TRUE) Returns P(X<7) for Poisson with = 5. Note: false returns the probability density P(X = 7) –EXPONDIST =EXPONDIST(40,1/20,TRUE) Returns P(X<40) for the exponential distribution with 1/  =20 Note: false returns the probability density f(40)=20exp(-20(40)) Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Conditional functions: –IF =IF(A4>4,B1+B2, B1 – B2) Returns B1+B2 if A4>4, and B1 – B2 if A4  –SUMIF =SUMIF(F1:F12,“>60”,G1:G12) Returns G1+G2+…+G12 only if F1+F2+…+F12>60 Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO –VLOOKUP=VLOOKUP(6.6,A1:E6,4) If the values in column A of a given table [A1:E6] are sorted (in an ascending order), VLOOKUP finds the largest value in column A that is less than or equal to 6.6, identifies the row it belongs to, and returns the value in the fourth column that correspond to this row. Note: If the values in column A are not sorted, =VLOOKUP(6.6,A1:E6,4,FALSE) finds the value 6.6 in column A, identifies the row it belongs to, and returns the value in the fourth column that corresponds to this row. Basic Excel functions and operators

A. Ruiz Méthodes d ’aide à la décision en RO Statistical/Optimization –Data Analysis [Selected from the Tools menu]. Useful entries: Descriptive Statistics Regression Exponential Smoothing Anova Basic Excel functions and operators