Question

A mechanical workshop has registered that three cars with electrical problems arrive in the morning, eight with mechanical problems and three with sheet metal problems, and in the afternoon two with electrical problems, three with mechanical problems and one with sheet metal problems.
a) Construct the contingency table with the previous data.
b) Calculate the percentage of those who come in the afternoon.
c) Calculate the percentage of those who attend due to mechanical problems.
d) Calculate the probability that a car with electrical problems will come in the morning.

Answer 1

a)  contingency table

	Electrical	Mechanical	sheet metal	Total
Morning	3	8	3	14
afternoon	2	3	1	6
Total	5	11	4	20

b) Calculate the percentage of those who come in the afternoon.

= (Number of cars that come in the afternoon / Total number of cars)*100 =(6/20)*100 = 30%

percentage of those who come in the afternoon = 30%

c) Calculate the percentage of those who attend due to mechanical problems

= (Number of cars with  mechanical problems / Total number of cars)*100 =(11/20)*100 = 55%

percentage of those who attend due to mechanical problems = 55%

d) Calculate the probability that a car with electrical problems will come in the morning

probability that a car with electrical problems will come in the morning =

Number of cars with electrical problems that come in the morning / Total number of cars with electrical problems

= 3/5=0.6

Probability that a car with electrical problems will come in the morning = 0.6