Correlation coefficients. image attached for the problem.

a. 11
b. 9
c. 3
d. 5

A

Step-by-step explanation:

y bar basically means the average of the y-values.

To get the average, we add up all the y-values in the table and divide by the total number of values (here we have 5 values). Hence,

y bar =

correct answer is A

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.