To study the effect of advertising expenditures (measured in thousands of pounds) and price, the partial slope coefficient for advertising is 0.875. This means that, on average, for every additional £1,000 spent on advertising, sales of the Brunel burger are expected to increase by 875 units (in thousands). The estimated standard error for this coefficient is 0.325. To test if this coefficient is significantly different from zero at the 95% confidence level, we can compute the t-statistic: t.