What do the chi-square test for independence, the Pearson correlation, and simple linear regressions all have in common

They all test relationship when it involves two variables

Explanation:

All of the statistical methods listed above all measure the relationship between two variables.

The Chi Square test tests the relationship between two nominal/categorical variable groups.

The Pearson correlation test tests relationship between two continuous variables using the Pearson correlation coefficient to determine statistical relationship between them.

The simple linear regression measures relationship between two variables: dependent/response variable and independent/explanatory variable, to see if a relationship exists between by way of influence of the independent variable on the dependent variable.

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt