iTESTER info  Home

Tester is coded by Tim Lovett. The encryption uses modified code for the Blowfish cipher (Bruce Schneier) and by DI Management (http://www.di-mgt.com.au/crypto.html#BlowfishVB), (somewhat stripped down by TL). Mathematical parsing code is by Ionut Alex. Chitu, http://deadline.3x.ro (TL added Atan2 functionality and handling of serial signs +-, --,  etc) (TL added matrix solver Aug 2009)


Test Specifications

(These may be modified at any time)
Question Types
Multiple Choice: Minumum of 2 options (true/false), maximum of 6 options. 
V
Question stem
Image  (relative filename)
correct answer
distractor
distractor
distractor

What is a Fatigue Strength?

images/endurance_limit.gif
The stress that a material can withstand for a certain number of cycles.
Maximum stress that will allow the material to cycle indefinitely.
The maximum length of fatigue fracture before failure occurs.
The same as the yield point (or elastic limit).

#Numerical: Also continued questions (cont) that uses previous variables and allows more (but not less). Up to 26 variables per question. See operators
N
Question stem
Image  (relative filename)
formula
units

#(cont) What is the area of a circle with #(12,25,2) mm diameter?

images/circle.gif
0.25*Pi*#a^2
mm2

@Selection: Choose labels that match on a diagram. Max number of labels = 78  (A-Z...AA-ZZ...1-26)
S
Question stem
Image  (relative filename)
correct labels (alphabetic order)
number of labels displayed

@Select all forces for a FBD of the Hand Lever. (Ignore its own gravity)
images/pipe_wrench.jpg
A,E,H
16

%Word: List of text strings. Max no of strings = 6. Max number of correct answers per string = 20.
W
Question stem
Image  (relative filename)
correct answer(s) for word 1
correct answer(s) for word 2

%Newton's ..... law can be epressed by the equation: Force. =  mass * .........

images/mass.jpg
2nd,2,second
acceleration,a

$Matching: Matching names against labels on a picture. Max number of matches = 12.
M
Question stem
Image  (relative filename)
list of names
list of matching labels

$Type the correct label for each valve image that matches the description below.
images\compare_valves.jpg
Butterfly valve,Globe valve,Needle valve,Ball valve,Diaphragm valve,Gate Valve  
E,C,D,F,A,B


Units 
Numerical Questions only
Unit DescriptionPrefix Multiplier
Available?
DisplayedText
Code
Do not display Units frame--Number
No Units-No UnitsNo Units
Celcius
-oCC
degrees of angle-degdeg
grams-gdeg
Hertz: cycles / secondYesHzHz
JoulesYesJJ
Joules / kg-J/kgJ/kg
Joules / kg Kelvin-J/kgKJ/kgK
Kelvin-KK
per Kelvin-1/K1/K
kilograms-kgkg
kilogram metres squared-kg.m2kgm2
kilogram mm squared-kg.mm2kgmm2
kilograms/ metre-kg/mkg/m
kilograms/ square metre-kg/m2kg/m2
kilograms/ cubic metre -kg/m3kg/m3
kilograms / s-kg/skg/s
kilogram metres / s-kg.m/skgm/s
kilometers per hour-km/hkm/h
metresYesmm
metres per second-m/sm/s
metres per second squared-m/s2m/s2
metres squared-m2m2
metres squared / sec-m2/sm2/s
cubic metres-m3m3
cubic metres / kilogram-m3/kgm3/kg
cubic metres / second-m3/sm3/s
millimeters-mmmm
millimeters / Kelvin-mm/Kmm/K
square millimeters-mm2mm2
cubic millimeters-mm3mm3
millimeters to the fourth-mm4mm4
NewtonsYesNN
Newton.metersYesN.mNm
Newton.millimeters-NmmNmm
Newton.seconds-N.sNs
Newtons / m-N/mN/m
Newtons / mm-N/mmN/mm
PascalsYesPaPa
Pascal.seconds-Pa.sPas
Radians-radrad
Radians per second-rad/srad/s
Radians / second squared-rad/s2rad/s2
SecondsYesss
WattsYesWW
Percentage-%%
AmperesYesAA
CoulombsYesCCb
FaradsYesFF
HenrysYesHH
OhmsYesOhmsR
VoltsYesVV
Volt AmperesYesVAVA

Operators
Numerical Questions only
OperatorDescription
(((a)))Unlimited nested brackets
e2.71828182845905
pi3.14159265358979
+addition
-subtraction
*multiplication
/division
a ^ bab
a @ blog b(a)
ln alog e(a)
abs(a)absolute value of a
exp(a)ea
sqrt(a)square root of a
int(a)integer of a
frac(a)a - int(a)
sin(a)sine of a
cos(a)cosine of a
tan(a)tangent of a
asin(a)inverse sine of a
acos(a)inverse cosine of a
atan(a)inverse tangent of a
sinh(a)hyperbolic sine of a
cosh(a)hyperbolic cosine of a
tanh(a)hyperbolic tangent of a

Functions
Numerical Questions only. All functions may contain formulas and may itself be included within other formulas.
FunctionDescription
atan2(a,b)Excel style: atan2(x,y)
Derive(function, x)Numerical Derivative
Find_root_Newton(function, xguess, precision)Find root of function 1
Find_root_bisection(function, x0, x1, precision)Find root of function 2
#a + Matrix["1,#a,-1,2,1,2,1,6,2,-1,1,#a^2", 3]
Maximum 8 rows x 9 columns. Permits matrix within formula and formula within any matrix entry.
Solve matrix for column 3 variable
1      4     -1      2
1      2      1      6
2     -1      1    16
Statistical Functions with formula variables
e.g. Mean[#a,#b,#c,#d-1,#e,#f,#g+5]
Also Range[], Median[], StDev[], StpDev[]
Common descriptive statistical terms. Matches Excel except Excel's StDevp was changed to StpDev.
Normal Distribution Conversion Function
NormX[mean,stdev,probability]
NormX[#a,#b,1/1000]
Find the value (x) below which the probablity is satisfied.
(Probability * 100 =  percentile)
Probablilty Conversion Function (Normal dist)
NormP[mean, stdev, x]
NormX[#a,#b,75] * 100
Uses bisection method to solve  probablity for given (x) value.
(Probability * 100 =  percentile)

Text Display Symbols
Any question stem. Multiple choice options (distractors) only.
DescriptionAscii CodeDisplayedText
Code
power of 0Chr$(186)A0A^0
power of 1Chr$(185) A1A^1 
power of 2Chr$(178) A2A^2 
power of 3Chr$(179)  A3A^3 
divisionChr$(247) -/-
multiplication
Chr$(215) X*
plus or minusChr$(177) +
-
+/-
degreesChr$(176)o<DEG>
Greek symbol phiChr$(216)<PHI2>
Greek symbol phi smallChr$(248)<PHI>
Greek symbol muChr$(181)
<MU>
Greek symbol betaChr$(223) <BETA>
boxChr$(127) [] <BOX>
Line FeedChr$(10)new line<LF>
1 DashChr$(151)_<->
3 Dashes3 x Chr$(151)___<3->
5 Dashes5 x Chr$(151)______<5->
10 Dashes10 x Chr$(151)__________<10->
1/4Chr$(188)1/4<1/4>
1/2Chr$(189)1/2<1/2>
3/4Chr$(190)3/4<3/4>

Graphical Display

TypeDescription
images\picture.jpgjpg, gif, png
Location relative to encrypted test file - e.g. images folder
images\machine.htmlhtml, flash
Location relative to encrypted test file - e.g. images folder
graph[#a*x + #b] 200Lcode generated graphical display:
Plots any mathematical valid function. E.g.  y = a x + b
where #a and #b are random variables from question stem
200 is initial scale (max X). L = locked zoom
point[#a,#b*3]Plots a point. Functions and variables permitted


For TEACHERS
Assessment Links and Resources

How to write Matching Questions:  http://web.utk.edu/~mccay/apdm/match/match_b.htm

Encryption;
Encryption is essential because the students download test files that contain sensitive information  (i.e. the correct answers and formulas). The Blowfish algorithm (128 bit) is a recognised secure cipher that is in the public domain. Blowfish is a keyed, symmetric block cipher, designed in 1993 by Bruce Schneier and included in a large number of cipher suites and encryption products. Blowfish provides a good encryption rate in software and no effective cryptanalysis of it has been found to date. Compared to the early versions of Tester (before Nov 15, 2008), the decryption  take a little longer - typically up to several seconds for a 50 question multiple choice test. (Mathematics tests tend to be a lot shorter since there is less text). No decryption occurs during the running of test.