For the 186 LDS9 records with both age and average systolic blood pressure available, a fitted regression line is
s=0.561a+97.7s=0.561a+97.7s=0.561a+97.7,
where a a\,a is age in years and s s\,s is average systolic blood pressure in mm Hg. Ages in the data set range from 17 to 85 years.
Use the model to estimate average systolic blood pressure for a 60-year-old.
Explain why using the model for a 10-year-old would be unreliable.
A student says that the model proves ageing causes systolic blood pressure to rise. Explain why this conclusion is not justified.
121 exam-style questions on OCR (MEI) A Level Maths 2.2 Data Presentation and Interpretation, covering 2.2.1 Types of data and standard diagrams, 2.2.2 Area in a histogram is proportional to frequency, 2.2.3 Cumulative frequency diagram, 2.2.4 Describe frequency distributions, 2.2.5 Samples and theoretical distributions, 2.2.6 Interpret a scatter diagram, 2.2.7 Distinct sections and outliers in scatter diagrams, 2.2.8 Correlation and causation, 2.2.9 Select or critique data presentation techniques, 2.2.10 Measures of central tendency, 2.2.11 Simple measures of spread, 2.2.12 Variance and standard deviation, 2.2.13 Outliers, 2.2.14 Cleaning data, and 2.2 Data Presentation and Interpretation. Each one has a worked solution and a mark scheme showing where the marks go.