QUESTION 3 The management of a supermarket was interested to examine the relationship between the number of product promotion time per day on the PA system and the number of daily units sold for the product. The following table gives the number of product promotion time for 7 days and the number of units sold.

Number of product promotion time per day	Number of units sold per day
15	11
22	22
42	30
30	26
18	17
12	15
38	23

a) Calculate the Pearson's product moment correlation coefficient and interpret its value obtained. (5 marks) b) Find the equation of the regression line that best fits the data. Interpret the meaning of slope obtained. (5 marks)