Sharp EL-531LH - Page 42

Mastering the Calculator using the Sharp EL-531LH 39
(x) = 1.3325 or 0.9341
Calculator keys: 2.015 × √(0.1366x
2
÷ 6 + 0.2x
2
÷ 6) = + 4.1333 – 3 =
Display reads 1.3325
then press + 4.1333 – 3 =
Display reads 0.9341
(xi) = 6.1111
Calculator keys: (100 – 90) x
2
÷ 90 + (50 – 60) x
2
÷ 60 + (20 – 30) x
2
÷ 30 =
2. The following data is on growth (in $m) in an economy over a 8 year period:
2.5 6.2 -2.1 0.04 8.2 7.4 2.1 -1.7
Calculate (i) Σx (ii) Σx
2
(iii) (Σx)
2
Explain in words what each of these mean.
To do this on the calculator, you must be in SD mode. Enter the data:
2.5 M+ 6.2 M+ 2.1 +/− M+ 0.04 M+ 8.2 M+ 7.4 M+ 2.1 M+ 1.7 +/− M+
Display reads n = 8
(i) 22.64 Press the key that says Σx ( )
This gives the total growth over the last 8 years
(ii) 178.4016 Press the key that says Σx
2
( ) This gives the sum of
the squares of the growth in each year
(iii) 512.5696 Press Σx and x
2
. This gives the square of the sum of the growth.
Press
4.1333 3.000–()2.015
0.1366
2
6
-------------------
0.2000
2
6
---------------
----
+±
100 90–()
2
90
-
---------------------------
50 60–()
2
60
-------------------------
20 30–()
2
30
---------------------
----
++