(i) To draw the histogram, calculate the frequency density for each class interval. Frequency density is given by \(\text{Frequency} / \text{Class Width}\).

For \(0.1 \leq t \leq 0.5\), Frequency = 11, Class Width = 0.4, Frequency Density = \(11 / 0.4 = 27.5\).

For \(0.6 \leq t \leq 1.0\), Frequency = 15, Class Width = 0.4, Frequency Density = \(15 / 0.4 = 37.5\).

For \(1.1 \leq t \leq 2.0\), Frequency = 18, Class Width = 0.9, Frequency Density = \(18 / 0.9 = 20\).

For \(2.1 \leq t \leq 3.0\), Frequency = 30, Class Width = 0.9, Frequency Density = \(30 / 0.9 = 33.33\).

For \(3.1 \leq t \leq 4.5\), Frequency = 21, Class Width = 1.4, Frequency Density = \(21 / 1.4 = 15\).

Draw bars with these heights on the histogram.

(ii) Calculate the mean time spent:

Find the midpoints of each interval: \(0.3, 0.8, 1.55, 2.55, 3.8\).

Multiply each midpoint by its frequency and sum these products: \((0.3 \times 11) + (0.8 \times 15) + (1.55 \times 18) + (2.55 \times 30) + (3.8 \times 21)\) \(= 199.5\).

Divide by the total frequency: \(199.5 / 95 = 2.1\).

Thus, the estimated mean time spent is 2.1 hours.