Final answer:
The sample size is 80 specimens. To determine the mean and standard deviation of the compressive strengths, the individual strength values for each specimen are necessary, which are not provided in the question.
Step-by-step explanation:
The question pertains to the field of material science within engineering, focusing on the elastic properties and compressive strengths of a new aluminum-lithium alloy. When discussing compressive strengths, the sample size refers to the number of specimens tested. In this scenario, the sample size is explicitly stated to be 80 specimens. The mean and standard deviation are statistical measures that describe the average strength and the variability of strengths within the sample, respectively. However, to calculate these values, the actual strength values for each specimen would be required, which are not provided in the question.
The subject matter includes concepts like breaking stress, tensile stress, and Young's modulus, key topics in the study of materials' responses to external forces. These concepts are essential when considering the mechanical properties of materials used in structures like aircraft, where safety and performance are critical.