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  (Lin):

Linear regression

  (Log):

Logarithmic regression

 

(Exp):

Exponential regression 

  (Pwr):

Power regression

(Inv):

Inverse regression

(Quad):  Quadratic regression

•  Always start data input with 

 (ScI)   to clear statistical memory.

•  Input data using the key sequence shown below.

•  The values produced by a regression calculation depend on the values input, and results can 

be recalled using the key operations shown in the table below.

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Summary of Contents for 2270443

Page 1: ...Operating Instructions RF CA 240 Scientific Calculator Item No 2270443 N FIX SCI SD EQ S A M STO REG CMPLX MAT VGT R I Eng r RCL STO hyp D R G 10 Disp ...

Page 2: ...afety precautions 5 4 Handling precautions 6 5 Two line display 7 6 Before getting started 7 7 Basic calculations 10 8 Memory calculations 14 9 Scientific function calculations 16 10 Statistical calculations 19 11 Technical information 26 11 Power Supply 31 12 Disposal 32 13 Technical data 33 2 ...

Page 3: ...tructions are part of this product They contain important notes on commissioning and handling Also consider this if you pass on the product to any third party Therefore retain these operating instructions for reference If there are any technical questions please contact www conrad com contact Up to date operating instructions Download the latest operating instructions via the link www conrad com d...

Page 4: ... as shown in the illustration slide the unit out of the cover After you are finished Holding the cover as shown in the illustration slide the unit out of the cover Always slide the keyboard end of the unit into the cover first Never slide the display end of the unit into the cover 4 ...

Page 5: ...rect heat or dispose of them by incineration Misuse of batteries can cause them to leak and damage nearby items and can create the risk of fire and personal injury Always make sure that the battery s positive and negative ends are facing correctly when you load it into the calculator Remove the battery if you do not plan to use the calculator for a long time Use only the type of battery specified ...

Page 6: ...emperatures Heat can cause discoloration or deformation of the calculators case and damage to internal circuitry Avoid use and storage in areas subjected to large amounts of humidity and dust Take care never to leave the calculator where it might be splashed by water or exposed to large amounts of humidity or dust Such conditions can damage internal circuitry Never drop the calculator or otherwise...

Page 7: ... enter the correct mode as indicated in the table below To perform this type of calculation Perform this key operation To enter this mode Basic arithmetic calculations COMP Standard deviation SD Regression calculations REG Pressing the key more than once displays additional setup screens Setup screens are described in the sections of this manual where they are actually used to change the calculato...

Page 8: ... your calculation into two or more parts Pressing the key recalls the last result obtained which you can use in a subsequent calculation See Answer Memory for more information about using the key Making corrections during input Use and to move the cursor to the location you want Press to delete the number or function at the current cursor position Press to change to an insert cursor Inputting some...

Page 9: ...n that is made up of two of more smaller expressions which are joined using a colon Example To add 2 3 and then multiply the result by 4 Exponential display formats This calculator can display up to 10 dig its Larger values are automatically displayed using exponential notation ln the case of decimal values you can select between two formats that determine at what point exponential notation is use...

Page 10: ...ol setting press the key a number of times until you reach the setup screen shown below Display the selection screen Press the number key or that corresponds to the setting you want to use Dot Period decimal point comma separator Comma Comma decimal point period separator Initializing the calculator Perform the following key operation when you want to initialize the calculation mode and setup and ...

Page 11: ...alues are displayed in decimal format automatically whenever the total number of digits of a fractional value integer numerator denominator separator marks exceeds 10 Example 1 Example 2 Example 3 Example 4 Results of calculations that mix fraction and decimal values are always decimal Decimal Fraction conversion Example 1 Decimal Fraction Example 2 Fraction Decimal 11 ...

Page 12: ...ess the A key a number of times until you reach the setup screen shown below Display the selection screen Press the number key or that corresponds to the setting you want to use Mixed fraction Improper fraction An error occurs if you try to input a mixed fraction while the d c display format is selected Percentage calculations Example 1 To calculate 12 of 1500 180 Example 2 To calculate what perce...

Page 13: ...calculations You can perform sexagesimal calculations using degrees hours minutes and seconds and convert between sexagesimal and decimal values Example 1 To convert the decimal value 2 258 to a sexagesimal value and then back to a decimal value Example 2 To perform the following calculation FIX SCI RND To change the settings for the number of decimal places the number of significant digits or the...

Page 14: ...calculation using the specified number of decimal places Internal rounding Press Norm to clear the Fix specifica Example 2 1 3 displaying result with two significant digits Sci 2 Press Norm to clear the Sci specification 8 Memory calculations Usee the key to enter the COMP Mode when you want to perform a calculation using memory COMP Internal calculation continues using 12 digits Specifies three d...

Page 15: ...lculation result produced by pressing can be used in the next calculation The result of a calculation can also be used with a sub sequent Type A function Independent memory Values can be input directly into memory added to memory or subtracted from memory lndependent memory is convenient for calculating cumulative totals Independent memory uses the same memory area as variable M To clear independe...

Page 16: ...Wait for the result to appear on the display before starting the next calculation 3 14159265359 Trigonometric Inverse trigonometric functions To change the default angle unit degrees radians grads Press the key a number of times until you reach the angle unit setup screen shown below Press the number key or that corresponds to the angle unit you want to use 90 radians 100 grads Example 1 Example 2...

Page 17: ...ns Example 1 Example 2 Common and natural logarithms Antilogarithms Example 1 Example 2 Example 3 Example 4 Example 5 Square roots Cube roots Roots Squares Cubes Reciprocals Factorials Random numbers and Permutation Combination Example 1 Example 2 Example 3 17 ...

Page 18: ...alues can be produced using the numbers 1 through 7 Numbers cannot be duplicated within the same 4 digit value 1234 is allowed but 1123 is not Example 11 To determine how many different 4 member groups can be organized in a group of 10 individuals Angle unit conversion Press to display the following menu Pressing or converts the displayed value to the corresponding angle unit Example To convert 4 ...

Page 19: ...e of r or to display the value of Engineering notation calculations Example 1 To convert 56 088 meters to kilometers Example 2 To convert 0 08125 grams to milligrams 10 Statistical calculations Standard deviation Use the key to enter the SD Mode when you want to perform statistical calculations using standard deviation SD Always start data input with Scl to clear statistical memory Input data usin...

Page 20: ...ues Data input precautions inputs the same data twice You can also input multiple entries of the same data using To input the data 110 ten times for example press 110 10 You can perform the above key operations in any order and not necessarily that shown above While inputting data or after inputting data is complete you can use the and keys to scroll through data you have inputif you input multipl...

Page 21: ...u will not be able to input any more data if there is no memory left for data storage lf this happens press the key to display the screen shown below Press to exit data input without regis ering the value you just input Press if you want to register the value you just input without saving it in memory lf you do this however you will not be able to display or edit any of the data you have input To ...

Page 22: ...verse regression Quad Quadratic regression Always start data input with ScI to clear statistical memory Input data using the key sequence shown below The values produced by a regression calculation depend on the values input and results can be recalled using the key operations shown in the table below 22 ...

Page 23: ... quadratic regression Correlation coefficient r The following table shows the key operations you should use to recall results in the case of quadratic regression To recall this type of value Perform this key operation Regression coefficient C The values in the above tables can be used inside of expressions the same way you use variables 23 ...

Page 24: ...re at 1000hPa Finally calculate the coefficient of determination r2 and sample covariance 10 C 1003 hPa 15 C 1005 h Pa 20 C 1010 hPa 25 C 1011 hPa 30 C 1014 hPa In the REG Mode Each time you press to register your input the number of data input up to that point is indicated on the display n value Regression coefficient A 997 4 Regression coefficient B 0 56 Correlation coefficient r 0 982607368 Atm...

Page 25: ...ula for quadratic regression is y A Bx Cx2 Example Xi yi Perform quadratic regression to determine the regression formula terms for the data nearby Next use the regression formula to estimate the values for estimated value of y for xi 16 and estimated value of x for yi 20 29 1 6 50 23 5 74 38 0 103 46 4 118 48 0 In the REG Mode Regression Coefficient A 35 59856934 Regression Coefficient B 1 495939...

Page 26: ... the calculation again If the above steps do not correct the problem press the key The calculator performs a self check operation and deletes all data stored in memory if any abnormality is detected Make sure you always keep written copies of all important data Error messages The calculator is locked up while an error message is on the display Press to clear the error or press or to display the ca...

Page 27: ...sor located at the location of the error and make required corrections Arg ERROR Cause Improper use of an argument Action Press or to display the location of the cause of the error and make required corrections Order of operations Calculations are performed in the following order of precedence 1 Coordinate trensformation Pol x y Rec r θ 2 Type A functions With these functions the value is entered ...

Page 28: ... first Stacks This calculator uses memory areas called stacks to temporarily store values numeric stack and commands command stack according to their precedence during calculations The numeric stack has 10 levels and the command stack has 24 levels Astack error Stack ERROR occurs whenever you try to perform a calculation that is so complex that the capacity of a stack is exceeded Example Numeric s...

Page 29: ...es Internal digits 12 Accuracy As a rule accuracy is 1 at the 10th digit Functions Input range DEG RAD GRA DEG RAD GRA DEG Same as sinx except when RAD Same as sinx except when GRA Same as sinx except when nPr 29 ...

Page 30: ...on error is 1 at the 10th digit In the case of exponential display calculation error is 1 at the last significant digit Errors are cumulative in the case of consecutive calculations which can also cause them to become large This is also true of internal consecutive calculations that are performed in the case of nPr nCr etc In the vicinity of a function s singular point and point of inflection erro...

Page 31: ...ures become dim To replace the battery 1 Press to turn power off 2 Remove the six screws that hold the back cover in place and then remove the back cover 3 Remove the old battery 4 Load a new battery into the unit with its positive and negative ends facing correctly 5 Replace the back cover and secure it in place with the six screws 6 Press to turn power on Auto power off Calculator power automati...

Page 32: ...all used rechargeable batteries Disposing of them in the household waste is prohibited Contaminated rechargeable batteries are labelled with this symbol to indicate that disposal in the domestic waste is forbidden The designations for the heavy metals involved are Cd Cadmium Hg Mercury Pb Lead name on rechargeable batteries e g below the trash icon on the left Used rechargeable batteries can be re...

Page 33: ...V each Battery life Approximately 17 000 hours continuous display of flashing cursor Approximately 2 years when left with power turned off Dimensions 166 H X 85 W X 15 D mm Power consumption 0 0002 W Operating temperature 0 C to 40 C 32 F to 104 F 33 ...

Page 34: ... including translation reserved Reproduction by any method e g photocopy microfilming or the capture in electronic data processing systems require the prior written approval by the editor Reprinting also in part is prohibited This publication represent the technical status at the time of printing Copyright 2020 by Conrad Electronic SE ...

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