Identify two problems researchers experience in collecting data from a sample

Inappropriate Sampling size/technique

Decline in survey response/giving inadequate responses

Explanation:

Researchers sometimes anticipate getting the smallest sample size to generate outcomes to the study, moreover, the sample size should reflect a true representation of the population, else, the research will be bias.

Decline in survey response is a big challenge in collecting data, sometimes, participants just tick questionnaires and do not go through the questions with sincererity. They are often in haste to conclude and return the questionnaire.