In many cases groups can gain an advantage by misleading people with the misuse of statistics.
Common techniques used include:
Three dimensional graphs.
Axes that do not start at zero.
Axes without scales.
Graphic images that convey a negative or positive mood.
Assumption that a correlation shows a necessary causality.
Using statistics that are not truly representative of the entire population.
Using misconceptions of mathematical concepts
For example, the following pairs of graphs show identical information but look very different. Explain why.
Exercises - misuse of statistics
A company has tried to give a visual representation of the increase in their earnings from one year to the next. Does the graph below convince you? Critically analyse the graph.
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In a study conducted on a busy highway, data was collected about drivers breaking the speed limit and the colour of the car they were driving. The data were collected during a 20 minute time interval during the middle of the day, and are presented in a table and pie chart below.
Conclusions made by a novice based on the data are summarised as follows:
“People driving white cars are more likely to break the speed limit.”
“Drivers in blue and red cars are more likely to stick to the speed limit.”
A record label produces a graphic, showing their advantage in sales over their competitors. Identify at least three devices they have used to influence and mislead the readers impression.
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In an effort to discredit their competition, a tour bus company prints the graph shown below. Their claim is that the competitor is losing business. Can you think of a better explanation?
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To test a theory, 8 different offices were monitored for noise levels and productivity of the employees in the office. The results are graphed below.
The following statement was then made:
“If an office environment is noisy, this leads to poor productivity.”Explain the flaws in this thinking.
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Summary of definitions
The mean of a data set,
, denoted by
, is the average of the data values, and is calculated as:
The median is the centre data value in a data set that has been ordered from lowest to highest
The mode is the data value that occurs most often in a data set.
The following presentation summarises what you have learnt in this chapter. Ignore the chapter number and any exercise numbers in the presentation.
Summary
Data types
Collecting data
Samples and populations
Grouping data
TallyFrequency
bins
Graphing data
Bar and compound bar graphsHistograms and frequency polygons
Pie chartsLine and broken line graphs
Summarising data
Central tendency
MeanMedian
ModeDispersion
RangeQuartiles
Inter-quartile rangePercentiles
An engineering company has designed two different types of engines for motorbikes. The two different motorbikes are tested for the time it takes (in seconds) for them to accelerate from 0 km/h to 60 km/h.
Test 1
Test 2
Test 3
Test 4
Test 5
Test 6
Test 7
Test 8
Test 9
Test 10
Average
Bike 1
1.55
1.00
0.92
0.80
1.49
0.71
1.06
0.68
0.87
1.09
Bike 2
0.9
1.0
1.1
1.0
1.0
0.9
0.9
1.0
0.9
1.1
What measure of central tendency should be used for this information?
Calculate the average you chose in the previous question for each motorbike.
Which motorbike would you choose based on this information? Take note of accuracy of the numbers from each set of tests.
A company wanted to evaluate the training programme in its factory. They gave the same task to trained and untrained employees and timed each one in seconds.
Trained
121
137
131
135
130
128
130
126
132
127
129
120
118
125
134
Untrained
135
142
126
148
145
156
152
153
149
145
144
134
139
140
142
Find the medians and quartiles for both sets of data.
Find the Interquartile Range for both sets of data.
Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you.
Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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