As Safety, Health and Environmental (SHE) consultant, the occupational health nurse of a large tyre production plant advises you that a large number of workers in the same production area are visiting the clinic each day to receive simple medication for headaches. In some cases the headaches are severe, and some workers believe that their headaches are caused by the high air temperatures during the day which they have reported to their union.

Your environmental investigation shows that temperatures at different sites in the plant are similar, but vary greatly on a day to day basis, suggesting poor ambient temperature control. The nurse supplies a daily record of all headaches of a similar type of 15-days, as well as details of the number of people employed in the factory each day. The production engineer supplies records of mean production area temperature during each daily shift. These data are tabulated here.

Table: Employees with headaches and corresponding mean production area temperature

Day	Number of employees complaining of headaches	Total number of employees in production area on that day	Mean air temperature(C) in production area on that day
1	25	280	26
2	22	285	26
3	23	300	24
4	21	288	22
5	17	290	18
6	28	280	28
7	19	300	19
8	18	300	19
9	20	290	20
10	19	298	17
11	17	190	19
12	14	194	19
13	13	198	17
14	12	187	16
15	30	178	29

1. Plot a graph using Excel and insert a line of best fit line.

2. CalculatePearson's Product Moment Correlation Coefficient 'r' (notr²) using Excel's "insert function" ( f_x). (write formula).

3. a short comment on your observations based on this graph and 'r'.