A researcher wants to study the opinions of city residents about a new park. They stand at the park entrance at 10:00 AM on a Tuesday and survey the first 50 people they see. What is the most significant source of bias in this method?

When using a Random Number Generator (RNG) to select a simple random sample of size $n$, why is it essential to ensure the generated numbers are distinct?

In the context of mathematical modeling, when we use one variable to predict the values of another, the variable used as the basis for the prediction is known as the:

If a specific data point $(x_i, y_i)$ in a bivariate set satisfies $$ and , in which quadrant relative to the mean point does it lie, and what is the sign of its contribution to the covariance?

A researcher is studying the relationship between the concentration of a certain fertilizer ($x$) and the height of sunflower plants ($y$). If the goal is to predict how tall a sunflower will grow based on a specific amount of fertilizer used, which variable is the independent variable?