Fit a least-squares line to model long-term trends in time series data.

The table below shows the number of tourist visits (in thousands) to a regional park for eight consecutive years. (a) Calculate the equation of the least-squares regression line, where $t$ is the number of years since 2016 and $V$ is the number of visits in thousands. Give your answer in the form $V = a + bt$, correct to one decimal place. [2 marks] (b) Use your regression line to estimate the number of tourist visits in 2025, to the nearest thousand. [1 mark]

A small business recorded its monthly sales over eight months. Use your calculator to determine the gradient of the least-squares line fitted to the data in the table, correct to two decimal places.