The table below shows the price changes of fuel per litre year-on-year between August 2006 and August 2016.

The petrol prices are: R7.04, R7.01, R10.40, R7.69, R8.17, R10.40, R11.04, R13.55, R14.33, R13.26, R12.35.
R10.40 appears twice, while all other prices appear once.

The mode is the value that appears most frequently.
The mode of the price of petrol is $\boxed{\text{R10.40}}$.

1.1.2

The diesel prices are: R6.54, R6.51, R11.27, R6.65, R7.38, R9.30, R10.25, R12.48, R11.80, R10.96, R12.35.
Each price appears only once.

Since all values appear with the same frequency (once), there is no mode for the diesel prices.
The mode of the price of diesel is $\boxed{\text{No mode}}$.

1.1.3

There are 11 prices (from 2006 to 2016).

Rounding to two decimal places for currency:
The mean price of petrol is $\boxed{\text{R10.48}}$.

1.1.4

Petrol price in 2014 = R14.33
Petrol price in 2015 = R13.26

Diesel price in 2014 = R11.80
Diesel price in 2015 = R10.96

Since R1.07 > R0.84, petrol showed a greater reduction.
$\boxed{\text{Petrol showed a greater reduction}}$.

1.1.5

Petrol prices: R7.04, R7.01, R10.40, R7.69, R8.17, R10.40, R11.04, R13.55, R14.33, R13.26, R12.35.
Minimum petrol price = R7.01
Maximum petrol price = R14.33

Diesel prices: R6.54, R6.51, R11.27, R6.65, R7.38, R9.30, R10.25, R12.48, R11.80, R10.96, R12.35.
Minimum diesel price = R6.51
Maximum diesel price = R12.48

The difference between the ranges is $\boxed{\text{R1.35}}$.

1.1.6

Order the petrol prices: R7.01, R7.04, R7.69, R8.17, R10.40, R10.40, R11.04, R12.35, R13.26, R13.55, R14.33.
There are 11 prices, so the median is the $\frac{11+1}{2} = 6^{\text{th}}$ value.
Median petrol price = R10.40.

Order the diesel prices: R6.51, R6.54, R6.65, R7.38, R9.30, R10.25, R10.96, R11.27, R11.80, R12.35, R12.48.
There are 11 prices, so the median is the $\frac{11+1}{2} = 6^{\text{th}}$ value.
Median diesel price = R10.25.

The difference between the medians is $\boxed{\text{R0.15}}$.