Using a Calculator for Statistics Casio fx-82MS Mean and Standard deviation 1. Turn calculator on! [ON] 2. Put into Statistical Mode [MODE][2] 3. Clear the statistical memory [SHIFT][CLR][1][=] ([CLR] is next to [ON]) [STAT CLEAR shows on the screen – you can enter data now] (Clear the statistical memory each time you have a new data set to work with – very important!) 4. To enter data key in each piece of data then press [M+] For example, to enter (18, 23, 20, 21, 24, 23, 21, 21, 15, 19, 24) 18 [M+] 23 [M+] 20 [M+] 21 [M+] 24 [M+] 23 [M+] 21 [M+] 21 [M+] 15 [M+] 19 [M+] 24 [M+] 5. n (the number of pieces of data) is shown on the screen 6. To find the mean ( x ): [SHIFT][2][1][=] (11) (20.82 (2dp)) 7. To find the standard deviation: [SHIFT][2][2][=] (σ) if the data is from a population [SHIFT][2][3][=] (s or σ n1 ) if the data is from a sample (2.62 (2dp)) (2.75 (2dp)) 8. To enter grouped data: key in each piece of data then press [SHIFT] [,] frequency [M+] ([,] is on the left of [M+]) For example Frequency Table for the number of faults in a component Number of Faults Frequency 0 28 1 11 2 4 0[SHIFT][,]28[M+] 1[SHIFT][,]11[M+] 2[SHIFT][,]4[M+] For this data n = 43, mean ( x )= 0.44, sample standard deviation (s or σ n1 ) = 0.67 To find x 2 , x, or n; press [SHIFT] [1] then choose the appropriate statistic Unitec: D:\308870190.doc Correlation / Linear Regression Calculations 1. Turn calculator on! [ON] 2. Put into Regression Mode [MODE][3] 3. Choose linear regression [1] 4. Clear the statistical memory [SHIFT][MODE] [=] ([CLR] is next to [ON]) (do this each time you have a new data set to work with – very important!) 5. To enter data, key in x variable [,] y variable [M+] ([,] is on the left of [M+]) For example, to enter data in this table x variable 5 8 12 y variable 100 118 124 5 [,]100 [M+] 8 [,] 118 [M+] 12 [,] 124 [M+] For all regression statistics key [SHIFT][2] – S-VAR When you press this key you may not be able to see what you require – you must scroll along with the big replay key in the centre of the calculator to see the statistic before you key in its number You must key [AC] between each statistic 6. To find r (the correlation co-efficient): [SHIFT] [2] [3] [=] (0.935) 7. To find r² (the co-efficient of determination) square r (0.874) 8. To find the linear regression equation y = a + bx [SHIFT] [2 ] [1] [=] for a [SHIFT] [2] [2] [=] for b (86.297) (3.324) 9. To predict y from your regression equation: ŷ Key in x value say [9] and then [SHIFT] [2] scroll [2] ŷ [=] (If x = 9, y = 116.2) Unitec: D:\308870190.doc