A-Level Maths H1 Quiz - Graphs Coordinate Geometry
Name: ____________________
Class: ____________________
Date: ____________________
Score: ________ / 55
Duration: 90 Minutes
Total Marks: 55
Instructions:
- Answer all questions.
- Use of a non-CAS Graphing Calculator (GC) is expected.
- Show all necessary working.
- Give your answers to 3 significant figures unless specified otherwise.
Section A: Scatter Diagrams and Correlation (Questions 1–7)
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A researcher collects data on the number of hours spent studying (x) and the test scores (y) of 10 students.
(a) Describe the steps you would take on your GC to generate a scatter diagram for this data. [1]
(b) If the scatter diagram shows points closely clustered around a straight line sloping upwards, what does this suggest about the correlation between x and y? [1]
Answer:
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Given a set of data where the product moment correlation coefficient r=−0.87.
(a) Describe the strength and direction of the linear relationship. [2]
(b) Does this value of r imply that increasing x causes y to decrease? Explain your answer. [2]
Answer:
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A scatter diagram is plotted for the relationship between the age of a car (x in years) and its resale value (y in dollars).
(a) Sketch a typical scatter diagram for this relationship. [2]
(b) State whether you expect the correlation coefficient r to be positive or negative. [1]
Answer:
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For a given dataset, the regression line of y on x is y=4.2x+15.8.
(a) Interpret the meaning of the gradient 4.2 in the context of the variables x and y. [2]
(b) Predict the value of y when x=10. [1]
Answer:
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A student uses the regression line y=0.5x+20 to predict a value. The original data for x ranged from 10 to 50. The student predicts y for x=120.
(a) Is this an example of interpolation or extrapolation? [1]
(b) Explain why the prediction for x=120 might be unreliable. [2]
Answer:
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Given the summary statistics ∑x=50,∑y=100,∑x2=300,∑xy=600 for n=10 pairs of data.
(a) Calculate the mean of x and the mean of y. [2]
(b) Calculate the gradient m of the least squares regression line y=mx+c. [3]
Answer:
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On a GC, a student plots a scatter diagram and finds that the points form a distinct curve rather than a straight line.
(a) Is the product moment correlation coefficient r a suitable measure of the relationship in this case? Justify your answer. [2]
Answer:
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Section B: Regression and Linear Modelling (Questions 8–14)
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The regression line of y on x is y=−2.5x+100.
(a) Find the value of y when x=0. [1]
(b) Find the value of x when y=50. [2]
Answer:
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A dataset has a regression line y=1.2x−5.
(a) If every y-value in the original dataset is increased by 10, what is the new equation of the regression line? [2]
(b) If every x-value is doubled, how does the gradient of the regression line change? [2]
Answer:
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A researcher finds the regression line of T (Temperature) on H (Humidity) to be T=−0.15H+32.
(a) If the humidity increases by 10%, by how many units is the temperature expected to change? [2]
(b) If the current humidity is 60%, predict the temperature. [2]
Answer:
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Given the regression line y=3.1x+12.4, and the mean values xˉ=5 and yˉ=27.9.
(a) Verify that the regression line passes through the point (xˉ,yˉ). [2]
(b) If a new data point (6,30) is added, will the gradient m necessarily increase? Explain. [2]
Answer:
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A scatter diagram shows a very strong positive linear correlation (r=0.98).
(a) Describe the visual appearance of the points relative to the regression line. [2]
(b) If r were 0.10, how would the scatter diagram look different? [2]
Answer:
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For a set of data, the regression line of x on y is x=0.4y+2.
(a) Is this the same line as the regression line of y on x? Explain. [2]
(b) Rearrange the equation to express y in terms of x. [2]
Answer:
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A company models the relationship between advertising spend (x) and sales (y). The regression line is y=5.2x+100.
(a) What is the estimated sales if the advertising spend is zero? [1]
(b) If the company wants to increase sales by 52 units, how much more should they spend on advertising? [2]
Answer:
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Section C: Coordinate Geometry and Curve Analysis (Questions 15–20)
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A curve C has the equation y=2e0.5x.
(a) Find the gradient of the curve at the point where x=0. [2]
(b) Find the equation of the tangent to the curve at x=0 in the form y=mx+c. [3]
Answer:
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A curve is defined by y=ln(x+2).
(a) Find the x-intercept of the curve. [2]
(b) Determine the equation of the vertical asymptote of the curve. [2]
Answer:
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Consider the curve y=x−14.
(a) Find the coordinates of the point on the curve where the gradient is −4. [3]
(b) Find the equation of the normal to the curve at this point. [3]
Answer:
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A curve C has the equation y=x2−4x+7.
(a) Find the coordinates of the stationary point of the curve. [3]
(b) Determine the nature of this stationary point using the second derivative test. [2]
Answer:
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The region R is bounded by the curve y=ex, the x-axis, the line x=0, and the line x=2.
(a) Set up the definite integral to find the area of R. [2]
(b) Calculate the exact area of R. [2]
Answer:
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A line L passes through the points (2,5) and (6,13).
(a) Find the equation of line L. [2]
(b) Find the coordinates of the point where line L intersects the curve y=x2+1. [4]
Answer:
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