This function performs konfound analysis on a linear model object produced by lm. It calculates the sensitivity of inferences for coefficients in the model. It supports analysis for a single variable or multiple variables.

## Arguments

- model_object
The linear model object produced by lm.

- tested_variable_string
The name of the variable being tested.

- alpha
Significance level for hypothesis testing.

- tails
Number of tails for the test (1 or 2).

- index
Type of sensitivity analysis ('RIR' by default).

- to_return
The type of output to return.