Sharon's Study Is Ecologically Valid?

Question 1.
When deciding on the research design, one choice is whether to use an experimental or non-experimental design. This depends on the aim of the study. If the aim is to test a prediction that two or more variables are simply associated with each other, the researcher may decide to use a non-experimental or correlational design. However, if the aim is to test a prediction that there is a causal relationship between two variables, then an experimental design is needed.
The correlational design examines the relationships between variables as they happen to occur, without altering people’s experiences.The correlational coefficient often is used to measure the association between variables and the results are normally presented graphically
To consider whether ‘Sharon’s Study’ is ecologically valid, we need to see if this study can be related to, or reflects everyday, real life.
Studies with high ecological validity take place when participants are within their usual surroundings and behaving naturally so that results can be generalised beyond the setting they were carried out in, whereas studies low in ecological validity cannot.
Based on this definition, ‘Sharon’s study’ is not ecologically valid due to potential biases related to the opportunity sampling technique, the questionnaire used and the environment of the study not being representative of a natural environment for the infants involved.
The sample group in this study is very small and is a poor representation of society. The researcher is using the easiest and most available opportunity sampling technique, risking to produce a biased sample. It consists of mothers and infants that Sharon works with in a local Children’s Centre.
Mothers who attend the classes belong to a very specific group and their responses to the questionnaire cannot be generalised to the wider population, unless Sharon specifies that her target population is the mothers with literacy
In the correlational analysis it is important to operationalise the variables by stating a clear way that the two independent variables (or co-variables) are going to be measured as this can affect the usefulness of this method. The hypotheses should clearly state the two variables that are being measured and what the researcher expects to find out. Whilst Sharon aims to look for a potential link between postnatal depression and the development of mother-infant relationships, her hypotheses does not reflect it and looks at a different co-variable instead (child ‘happiness’).
To make her conclusions, the researcher correlates the depression score for each mother with the total ‘happiness’ score for the mother’s child. The correlation she finds from using the statistical test is -0.12 which indicates very weak negative correlation: as the level of the mother’s depression increases, there is an insignificant chance that the mother’s child becomes less happy.
Scatterplots are a very useful type of descriptive statistics because they provide a graphical representation of the correlation between the variables. From the scatterplot the researcher can describe and summarise the data but cannot make the conclusion about the