Home / IB Mathematics SL 4.2 Presentation of data AI HL Paper 2- Exam Style Questions

IB Mathematics SL 4.2 Presentation of data AI HL Paper 2- Exam Style Questions- New Syllabus

Question

Sam is analyzing the total number of goals scored in each match of a professional soccer tournament held in \(2024\). He possesses a bar chart showing these results, although the bar representing the frequency of matches with exactly \(4\) goals is obscured.
Sam organizes the visible data from the bar chart into the following frequency table:
Goals per match (\(2024\))Frequency
\(0\)\(3\)
\(1\)\(11\)
\(2\)\(7\)
\(3\)\(k\)
\(4\)\(p\)
\(5\)\(1\)
(a) Determine the value of \(k\) by reading the provided bar chart.
Records indicate that the mean number of goals per match for the entire \(2024\) tournament was exactly \(2.2\).
(b) (i) Formulate an equation for the mean in terms of the unknown frequency \(p\).
(ii) Calculate the specific value of \(p\).
Statistics for the subsequent \(2025\) tournament are summarized in the box and whisker diagram below. By comparing this diagram with his \(2024\) data, Sam suggests that the distribution of goals remained stable over the two years.
 
 
 
(c) Identify two distinct statistical comparisons (choosing from range, skewness/symmetry, median, or interquartile range) that support Sam’s conclusion, referencing the calculated values from both years.
Sam intends to review recordings of all matches from the \(2024\) tournament in a randomized sequence, viewing each match exactly once. For the first match selected, let event \(F\) be defined as: “the total goals scored is either \(0\) or \(1\)”.
(d) Identify which event(s) from the list below are equivalent to the complement event \(F’\).
EventDescription
\(A\)Exactly \(2\) goals are scored in the match
\(B\)More than \(1\) goal is scored in the match
\(C\)At least \(2\) goals are scored in the match
\(D\)\(0\) or \(1\) goal is scored in every match except this one
\(E\)The score of \(0\) or \(1\) is not achieved in any match of the tournament
(e) Given that the first match Sam views contained exactly \(1\) goal, find the probability that the second match he views also contains exactly \(1\) goal. Express your result as a fraction.
(f) Calculate the probability that Sam observes \(5\) goals in the first match and \(0\) goals in the second match he views.

Most-appropriate topic codes (IB Mathematics: Applications and Interpretation):

SL 4.1: Discrete data and sampling concepts — part (a)
SL 4.2: Production and understanding of box and whisker diagrams — part (c) 
SL 4.3: Measures of central tendency (mean/median) and dispersion (IQR/range) — parts (b), (c) 
SL 4.5: Concepts of sample space, probability, and complementary events — part (d)
SL 4.6: Probability rules and calculation of combined events — parts (e), (f) 
▶️ Answer/Explanation

(a)
From the bar graph provided in the context, the frequency for \(3\) goals is identified as \(5\).
\(\boxed{5}\)

(b)
(i) Mean \(= \frac{\text{Total Goals}}{\text{Total Matches}}\).
Total Matches \(= 3 + 11 + 7 + 5 + p + 1 = p + 27\).
Total Goals \(= (0 \times 3) + (1 \times 11) + (2 \times 7) + (3 \times 5) + (4 \times p) + (5 \times 1) = 45 + 4p\).
Given Mean \(= 2.2\), the equation is: \( \boxed{45 + 4p = 2.2(p + 27)} \)

(ii) Solving for \(p\):
\(45 + 4p = 2.2p + 59.4\)
\(1.8p = 14.4\)
\(p = 8\).
\(\boxed{8}\)

(c)
From the \(2024\) data: Total matches \(= 35\). Median is at the \(18^{th}\) position \(= 2\). \(Q_1\) is at the \(9^{th}\) position \(= 1\). \(Q_3\) is at the \(27^{th}\) position \(= 4\). \(\text{IQR} = 4 – 1 = 3\). Range \(= 5 – 0 = 5\).
From the \(2025\) box plot: Median \(= 2\), \(Q_1 = 1\), \(Q_3 = 4\), \(\text{IQR} = 3\), Range \(= 5\).
Consistent observations:
1. The median number of goals is \(2\) for both years.
2. The interquartile range (\(\text{IQR}\)) is \(3\) goals for both years.

(d)
Event \(F\) is “scoring \(0\) or \(1\) goal”. The complement \(F’\) is “not scoring \(0\) or \(1\) goal”, which is equivalent to “scoring at least \(2\) goals”.
Equivalent events from the list: \(B\) and \(C\).
\(\boxed{B, C}\)

(e)
Total matches in \(2024 = 35\). Initially, there are \(11\) matches with \(1\) goal.
After watching one match with \(1\) goal, \(34\) matches remain, of which \(10\) contain \(1\) goal.
Probability \(= \frac{10}{34} = \frac{5}{17}\).
\(\boxed{\frac{5}{17}}\)

(f)
Probability of first match having \(5\) goals \(= \frac{1}{35}\).
Probability of second match having \(0\) goals (given the first was different) \(= \frac{3}{34}\).
Total Probability \(= \frac{1}{35} \times \frac{3}{34} = \frac{3}{1190}\).
\(\boxed{\frac{3}{1190}}\)

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