please answers and explain

Standardized scores or zscores allow us to compare variables with different units and different means and standard deviations, commonly used in health sciences and health practice, If mean weight fora sample of patients is 72 kgs and standard deviation is 6 kgs. What is the standardized score (or z-score) for a patient whose weight is 83 kgs? Use of brackets, at least for the numerator part, is highly recommended. Please remember only the final answer with two decimals is required (and not the whole working out). Which one ofthe following statements about study designs is INCORRECT? O Ecological studies are based on population level or group based aggregate data 0 Case control studies are observational analytic design. 0 Case Report and Case Series belong to descriptive category of study designs. 0 Cohort studies are usually descriptive design. 0 Difference between a true experiment and a quasiexperiment is the lack of random assignment of study subjects into experimental and control groups 0 Cross-sectional studies can be both descriptive as well as analytical