(a)
If is a probability density function then it must satisfy .
Observe the graph:
The graph of is a triangular region.
Find .
Calculate the area under the graph of with from to .
The triangle height is units and base is units.
Area of the triangle .
.
and for all .
Therefore, the function whose graph is shown is a probability density function.
(b)
(i)
Find .
.
.
From the graph, .
Find .
Calculate the area under the graph of with from to .
The triangle height is units and base is units.
.
.
(b)
(ii)
Find .
.
Calculate the area under the graph of with from to .
From part (b)(i) .
.
Estimate the area under the graph of with from to .
The triangle height is units and base is units.
.
.
.
(c)
The mean of any probability density function is defined to be .
.
Observe the graph:
Find .
if .
.
Find .
if .
.
The mean is .
.
(a), whose graph is shown is a probability density function.
(b) ; .
(c) .
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