Final answer:
The appropriate quantitative research designs for the sample research titles are: correlational, experimental, quasi-experimental, pre-experimental, and descriptive.
Step-by-step explanation:
For the first research title, 'Relationship between academic stressors and learning preferences of senior high school students,' a correlational research design would be appropriate. This design aims to determine the relationship between two variables, academic stressors and learning preferences. The researcher can collect data on both variables and analyze their relationship using statistical methods.
For the second research title, 'Reading electronic learning materials as a support for vocabulary of grade 1 pupils,' an experimental research design would be appropriate. The researcher can divide the grade 1 pupils into two groups, one using electronic learning materials and the other using traditional learning materials. Their vocabulary improvement can then be compared to see if the electronic learning materials have a positive impact.
For the third research title, 'Impact of the implementation of COVID-19 health protocols in supermarkets on consumer behaviors,' a quasi-experimental research design would be appropriate. Since the implementation of COVID-19 health protocols in supermarkets is not under the control of the researcher, a true experiment cannot be conducted. However, the researcher can still compare consumer behaviors before and after the implementation to identify any changes.
For the fourth research title, 'Effects of morning exercise on the health anxiety level of senior citizens,' a pre-experimental research design would be appropriate. The researcher can measure the health anxiety level of senior citizens before they start the morning exercise and compare it to their anxiety level after a period of engaging in morning exercise.
For the fifth research title, 'Measuring the gadgets usage of children at home during COVID-19 community quarantine,' a descriptive research design would be appropriate. The researcher can collect data on the usage of gadgets by children at home during the COVID-19 community quarantine period and describe patterns and trends in their usage.