Part (a)
Mean =

Range = 25 - 10 = 15
Median,

= 16 (Refer to the first picture)
Lower Quartile,

= 10
Upper Quartile,

= 22
Interquartile Range, IQR =

Part (b)
The box plot is shown in the second picture below
Part (c)
Mean = 16
Subtracting 16 from each data value, find sum of the square of each answer and divide by 6


Standard deviation =

(rounded to 2 dp)