a) The results of plotting the points on a graph should look like the picture below.
b) The line of best fit should look like the green line below.
To predict the weight of someone who’s 190cm tall, draw a line up from 190cm to the line of best fit, and then across from that line over to the weight axis. The prediction, according to this line of best fit is 95kg. Your line of best fit may be slightly different, in which case any answers between 93kg and 97kg are acceptable.
This might not be accurate because we are extrapolating, and the pattern outside the range of the data might change.