A dataset records study time (hours) and test score (points) for eight students:
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Practice IB Mathematics Analysis and Approaches (AA) Topic SL 4.4—pearsons, Scatter Diagrams, Eqn of y on x with authentic exam-style questions for both SL and HL students. This question bank focuses on the exact syllabus content for SL 4.4—pearsons, Scatter Diagrams, Eqn of y on x and mirrors Paper 1, 2, 3 style where relevant.
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A dataset records study time (hours) and test score (points) for eight students:
…
The variables and are related by a power law of the form , where . The following table shows values of and .
(a) Find the value of and the value of .
(e) Find the smallest integer value of for which the model predicts that the colony exceeds bacteria.
(f) on the appropriateness of using the model to the number of bacteria after hours.
(e) Find an expression for the daily profit in terms of .
(f) Find the minimum number of customers required to make a profit on a particular day.
(g) on the appropriateness of using this regression line to the revenue when the shop serves customers.
| 0 | 0.693 | 1.386 | 2.079 | 2.773 | |
|---|---|---|---|---|---|
| 0.693 | 2.773 | 4.852 | 6.931 | 9.011 |
The relationship between and can be modelled by .
(b) Hence find the value of and the value of .
A biologist studies the growth of a colony of bacteria. The table shows the time (in hours) and the number of bacteria in the colony at that time.
| (hours) | |||||
|---|---|---|---|---|---|
It is proposed that the relationship between and can be modelled by , where and are positive constants.
(a) Show that .
(b) Find the equation of the regression line of on in the form .
(c) Hence find the values of and .
A small coffee shop records the number of customers and the daily revenue (in dollars) over ten consecutive days.
The shop's daily cost (in dollars) is modelled by , where is the daily revenue.
(a) Find Pearson's product-moment correlation coefficient .
(b) on the result.
(c) Write down the equation of the regression line of on in the form .
A quarry records the total mass of stone, in tonnes, removed by the end of each of its first eight weeks of operation. Writing for the total by the end of week , the eight values are
The manager claims that the masses removed in successive weeks form an arithmetic sequence with first term and common difference .
For each , let .
(a) Show that, if the claim is correct, , and write down the gradient of against in terms of .
(b) Find and , and hence find the values of and that the claim would require, giving correct to three significant figures.
(c) Using these values, find the value of that the claim predicts, and find the difference between it and the recorded value.
(d) Using and , find the first week by the end of which the total mass removed exceeds tonnes.
(d) Use the model to the number of bacteria after hours.
(d) Use the regression equation to the revenue when customers are served on a particular day. Give your answer to the nearest dollar.