. 90 Question 27 (3 points) Saved A simple linear regression between sales (Y in $1000) and advertising (X in dollars) has the following equation: = 40,000 + 7 X increase of $7 in advertising is associated with an increase of $7,000 in sales increase of $1 in advertising is associated with an increase of $7 in sales increase of $1 in advertising is associated with an increase of $47,000 in sales increase of $1 in advertising is associated with an increase of $7,000 in sales Question 28 (3 points) A sample of 225 students from a university is selected. The population standard deviation for the amount they pay for grocery in a month is $75. The sample mean monthly amount they pay for grocery is $180. The