This is the formula to calculate beta for a company.

ΔSi=α+βi×ΔM+e

where:
ΔSi =change in the price of stock i.
α=intercept value of the regression.
βi=beta of the I stock return.
ΔM=change in the market price.
e=residual error term.

BY Best Interview Question ON 02 May 2021