A researcher investigated the relationship between the daily average PM2.5\text{PM}_{2.5}PM2.5 particulate concentration (in μg/m3\mu\text{g/m}^3μg/m3) and the mean peak expiratory flow rate (PEFR, in L/min) of a cohort of asthma patients over a period of 15 days. A Spearman's rank correlation was conducted to test the hypothesis that higher particulate levels are associated with a lower PEFR. The calculated value of rs r_s\,rs was -0.492. The critical value for a one-tailed test where p≤0.05 p \le 0.05\,p≤0.05 and N=15N = 15N=15 is 0.441. Write a significance statement for the correlation analysis performed on this data.
513 exam-style questions on OCR A Level Psychology Data recording, analysis and presentation. Each one has a worked solution and a mark scheme showing where the marks go.