IB Maths AA SL Topic 4: Statistics and probability questions

Exam-style questions in the shape of Paper 1 and Paper 2, with full markschemes. Read the markscheme, or type, photograph or draw your answer and get it marked.

Question 1

Paper 1, no calculatorMedium6 marks

A courier company records the delivery times for 40 trips on each of two routes. Figure 1 shows box-and-whisker diagrams for the two sets of times. For this comparison, use the median to represent typical delivery time and the interquartile range (IQR) to represent consistency.

0510152025303540Route BRoute ADelivery time (minutes)
(a)

State the median delivery time for each route.

[2]
(b)

Calculate the IQR for each route.

[2]
(c)

Recommend a route if the company wants both a shorter typical delivery time and more consistent delivery times. Justify your recommendation using the medians and IQRs.

[2]

Question 2

Paper 1, no calculatorMedium8 marks

A machine produces metal pins whose lengths are modelled by a normal distribution with mean 4242 mm and standard deviation 33 mm.

For this question, use the facts that approximately 68%68\% 95%95\% and 99.7%99.7\% of values lie within one, two and three standard deviations of the mean, respectively.

(a)

Estimate the percentage of pins with lengths between 3939 mm and 4545 mm.

[1]
(b)

Hence, estimate the percentage of pins with lengths between 3939 mm and 4848 mm.

[3]
(c)

A batch contains 800800 pins. Hence, estimate the number of pins in the batch with lengths between 3939 mm and 4848 mm.

[2]
(d)

A pin has length 5151 mm. Estimate the percentage of pins with lengths greater than 5151 mm, giving your reasoning.

[2]

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