In a study investigating the effects of temperature and humidity on plant growth, researchers use a factorial design where temperature levels are varied at 25°C and 30°C, and humidity levels are varied at 50% and 70%. Which of the following statements about interactions is most accurate in this context?

Let’s say a consumer goods company wishes to conduct a survey of its clients. They choose four goods at random from the ten goods groups and ask consumers in the chosen goods groups to score their experience on a scale of one to ten. Which of the following sampling techniques is being used in this situation?

Suppose you have a dataset called gdp_dat which contains values of the gross domestic product (gdp) at different time periods (year) across multiple countries (country). Suppose you want to calculate the number of data points available within each country. You can use

A study was carried out to predict the compressive strength of concrete using 2 predictor variables, Cement and Coarse_Aggregate. Find below the output of a regression model fitted to the data:

## (Intercept) Cement     Coarse_Aggregate
## 35.30       0.07       -0.02

What is the predicted compressive strength for a sample with Cement = 200 and CoarseAggregate = 1000?

A researcher wants to set up an experiment to study the effects of five different types of fertilisers on maize yield. They have access to a field where all plots are the same in terms of soil composition, and there is no reason to believe that there is a gradient of fertility in any direction. What experimental design should be used?

Jill is working on a project in which she is exploring the outcomes of a new educational curriculum on a sample of 3rd class primary school students in Ireland. Her ability to extend her findings to all 3rd class primary school students is an example of

A researcher would like to predict the probability of a cardiac arrest (cardiac arrest = 1, no cardiac arrest = 0) based on 4 predictors: age, body weight, exercise, and whether the person is a smoker or not. What would be the most suitable modelling strategy to be used in this case?

The plot below is an example of a

Which one of the situations presented below is an experimental study?

Which is the correct function for calculating the correlation between two variables x and y?