A psychologist is interested in measuring the quality of the relationship between mothers and their 1-year-old infants. They start by gathering 50 hours of video recording of each mother-child dyad. They code the interactions such that each dyad ends up with a "Security Score" (a number between 10 very low - 50 very high). They now wonder if they can assess the participants more quickly (50 hours of observations is a lot to gather and code). They draw up a survey of 50 questions and ask all the mothers to answer the questions. The researchers hope that the scores on the survey will mirror the scores on the observations. Here are the trials:
Trial 1: Observation: 11 (very low). Survey: 17 (low)
Trial 2: Observation: 11 (very low). Survey: 48 (very high)
Trial 3: Observation: 10 (very low). Survey: 29 (moderate)
The survey is .
A. reliable but not valid
B. valid but not reliable
C. neither reliable nor valid
D. both reliable and valid