Monthly Archives: April 2012

Mean,Standard Deviation ,Correlation coefficient, and regession line from sharp and Casio Calculators

The following give the methods for finding mean,standard deviation and correlation coefficients from your sharp or casio calculator

Casio fx-83GTPlus calculator

Given the frequency table find the mean and standard deviation

 

X 1 2 3 4
f 5 7 6 2                    

(i) press Mode 2,1  you will see a table as below imput the data as shown .Make sure the frequency is on by pressing shift mode (set up) down curser 1.

(ii)To get the mean press AC

(iii)Then shift 1.(iv) then 4 (on 83ES use 5) then 2 for the mean = 2.25.

(v)Then shift 1.and 3 for the standard deviation  = 0.94207.

 

  x y
1 1 = 5=
2 2 = 7=
3 3 = 6=
4 4 = 2=

Data  from  a  scatter Plot

 

 

                           X Score                (independent variable) Y score(Dependent Variable )
5 20
8 18
6 22
7 28
10 27

 

 

  x y freq
1 5 = 20=  
2 8 = 18=  
3 6 = 22 =  
4 7 = 28 =  
5 10 = 27 =  

(i) Press Mode 2 2 you will see a table as above  imput the data as shown .

(ii) When all the data has been entered Press AC

(iii) Press shift 1 then press (5 (var) then press 3 (r= 0.4174 ) this will give the correlation coefficient

(iv)To get the information  of the regression line press shift 1 then 5 then  1 (A)=16.19 this is the intercept  of the regression line and the Y axis .Press shift 1,5 then 2 (B= 0.9459) for the slope of the regression line. The regression line is in the form  y = 16.19+(0.9459)x  {y = a + bx}

For Casio Fx-83ES

(iii) Press shift 1 then press (7 (reg)then press 3 (r= 0.4174 ) this will give the correlation coefficient (iv)To get the slope of the regression line press shift 1 then 7(reg) then  1 (A)=16.19 this is the intercept  of the regression line and the Y axis .Press shift 1,7(reg) then 2 (B= 0.9459) for the slope of the regression line. The regression line is in the form  y=  A+bx   

For the sharp 531 use the following metho

Sharp W531 Calculator  and Statistics

The sharp w531 calculator can be used to find the mean and standard deviation as follows.

X 1 2 3 4
f 5 7 6 2

Method

(i) Press mode then pres 0 the screen reads STAT 0 (SD).

 

(ii) Input data as follows 1 (x,y) 5 Data (change) the screen reads DATA SET = 1 .

 

(iii)Then  2(x,y) 7 Data etc the screen will read DATA SET =2

 

 When all the data has been entered the screen will show DATA SET = 4.

(iv)To find the mean press RCL 4  (     ) =  2.25

(v)To find the standard deviation press RCL 6 ( ) = 0.94207

To find the Correlation coefficient from a scatter plot using Sharp w 531 calculator.

                           X Score               (independent variable) Y score(Dependent Variable )
5 20
8 18
6 22
7 28
10 27

 

Method :

(i)Press mode then press 1  SCREEN READS STAT 1 (LINE).

 

(ii)Input data as follows 5(x,y) 20 data screen reads data set = 1 . (as above)

 

(iii)Repeat for the rest of the data .after the last imput  screen should read DATA SET = 5.

 

(iv)To find the correlation coefficient press RCL  (DIVISION SYMBOL) =0.417

 

(v)To find the equation of the regression line (line of best fit)

 

(vi)To find the slope of the regression line pres RCL ) (RIGHT BRACKET ) = .946

 

(vii)To find where the regression line cuts the y axis pres RCL ( (LEFT BRACKET) = 16.189

(viii)Therefore the equation of the line of best fit is    y = 16.189 + (0.946)x

 The line of best fit is often written as  y  =  a+bx

Project Maths Easter Revision Courses at Ballinteer Institute

Easter Revision Courses in Project maths (paper 2) will take place at Ballinteer Institute in Dundrum from 10th to 14th April. The course will be given by John Brennan and will include all the strand 1 and strand 2 topics. A full set of notes on all topics will be provided .Call Ballinteer Institute at 01-2960006 .

It has also come to our attention that maths grind schools have been set up by non teachers and  others from the building industry claiming they are experts on Project maths .One of these tuition centres is passing off a well known Maths web sites notes as their own .

Students beware