Practice SL 4.4—Correlation of Data with authentic IB Mathematics Applications & Interpretation (AI) exam questions for both SL and HL students. This question bank mirrors Paper 1, 2, 3 structure, covering key topics like core principles, advanced applications, and practical problem-solving. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
In Lucy's music academy, eight students took their piano diploma examination and achieved scores out of 150. For her records, Lucy decided to record the average number of hours per week each student reported practising in the weeks prior to their examination. These results are summarized in the table below.
| Average weekly practice time (h) | 28 | 13 | 45 | 33 | 17 | 29 | 39 | 36 |
|---|---|---|---|---|---|---|---|---|
| Diploma score (D) | 115 | 82 | 120 | 116 | 79 | 101 | 110 | 121 |
Find Pearson's product-moment correlation coefficient, r, for these data.
The relationship between the variables can be modelled by the regression equation , where represents the diploma score and represents the average weekly practice time in hours. Write down the value of and the value of .
One of these eight students was disappointed with her result and wished she had practised more. Based on the given data, determine how her score could have been expected to alter had she practised an extra five hours per week.