Sarah believes there is a positive correlation between the amount of time spent practicing the piano and the score achieved in a music exam.
She calculates the product moment correlation coefficient between these two variables for a random sample of 20 students and obtains r=0.391r = 0.391r=0.391.
Carry out a suitable test to investigate Sarah's belief at a 5% level of significance.
State clearly
Practise Edexcel A Level Maths Regression, Correlation and Hypothesis Testing with exam-style questions for A Level Maths. 100 questions covering Exponential Models, Measuring Correlation, and Hypothesis Testing for Zero Correlation, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.