Answer:
D.
Step-by-step explanation:
Explanation for part 1.
To find the mean, find total then divide by number of data set
For college salaries
Sum=41+67+53+48+45+60+59+55+52+52+50+59+44+49+52=786
Number of samples=15
Mean= 786/15 =52.4 * $1000=$52400
For High school salaries
Sum=23+33+36+29+25+43+42+38+27+25+33+41+29+33+35=492
Number of samples =15
Mean= 492/15 = 32.8 *$1000= $32800
College grads make more money according to the means.
Explanation for part 2.
Treat the data as part of coordinates and graph then on the same scale and axis to visualize the trend and make comparison.In this case, the graph for the line of best fit is linear as attached.