An engineer investigates the fatigue life of a new aerospace-grade titanium alloy under cyclic stress. To determine how the mode of deformation affects material longevity, the engineer prepares two experimental groups of identical cylindrical specimens:
For both groups, the cyclic frequency is maintained at 15 Hz, the temperature is held constant at 23∘C23^\circ\text{C}23∘C, and the peak equivalent stress amplitude is set to 400 MPa. The engineer records the number of cycles to failure, NfN_fNf, for each specimen.
Which of the following statements correctly identifies the variables in this investigation?
Group 1 and Group 2 are conditions of the dependent variable, and the fatigue life (NfN_fNf) is the independent variable.
Group 1 and Group 2 are conditions of the independent variable, and the peak equivalent stress amplitude is the dependent variable.
Group 1 and Group 2 are control variables, and the fatigue life (NfN_fNf) is the dependent variable.
Group 1 and Group 2 are conditions of the independent variable, and the fatigue life (NfN_fNf) is the dependent variable.
Practise AQA A Level Psychology Research methods with exam-style questions for A Level Psychology. 100 questions covering Experimental method, Observational techniques, Self-report techniques, Correlations, Content analysis (A-level only), Case studies (A-level only), Scientific processes, Data handling and analysis, and Inferential testing (A-level only), matched to the AQA A Level Psychology (7182) 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.