In: Statistics and Probability
Make an A |
Make a B |
Make a C |
Make a D |
Make an F |
|
Sophomores |
.058 |
.101 |
.142 |
.092 |
.047 |
Juniors |
.055 |
.082 |
.102 |
.071 |
.030 |
Seniors |
.014 |
.023 |
.080 |
.063 |
.040 |
(a) What is the probability that a randomly selected student in Dr. Alan Math course is a Sophomore?
(b) What is the probability that a randomly selected student will make a D in Dr. Alan Math course?
(c) Given that a particular student made a B or better in Dr. Alan Math course, what is the probability that he or she took the course as a Junior?
(d) Given that a particular student in Dr. Alan Math course is a Senior, what is the probability that he or she will make an A in the course?
Make an A | Make an B | Make an C | Make an D | Make an F | Total | |
Sophomores | 0.058 | 0.101 | 0.142 | 0.092 | 0.047 | 0.44 |
Juniors | 0.055 | 0.082 | 0.102 | 0.071 | 0.030 | 0.34 |
Seniors | 0.014 | 0.023 | 0.080 | 0.063 | 0.040 | 0.22 |
Total | 0.127 | 0.206 | 0.324 | 0.226 | 0.117 | 1 |
(a) What is the probability that a randomly selected student in Dr. Alan Math course is a Sophomore?
P[ Sophomore ] = 0.44
Make an A | Make an B | Make an C | Make an D | Make an F | Total | |
Sophomores | 0.058 | 0.101 | 0.142 | 0.092 | 0.047 | 0.44 |
Juniors | 0.055 | 0.082 | 0.102 | 0.071 | 0.030 | 0.34 |
Seniors | 0.014 | 0.023 | 0.080 | 0.063 | 0.040 | 0.22 |
Total | 0.127 | 0.206 | 0.324 | 0.226 | 0.117 | 1 |
(b) What is the probability that a randomly selected student will make a D in Dr. Alan Math course?
Make an A | Make an B | Make an C | Make an D | Make an F | Total | |
Sophomores | 0.058 | 0.101 | 0.142 | 0.092 | 0.047 | 0.44 |
Juniors | 0.055 | 0.082 | 0.102 | 0.071 | 0.030 | 0.34 |
Seniors | 0.014 | 0.023 | 0.080 | 0.063 | 0.040 | 0.22 |
Total | 0.127 | 0.206 | 0.324 | 0.226 | 0.117 | 1 |
P[ make an D ] = 0.226
(c) Given that a particular student made a B or better in Dr. Alan Math course, what is the probability that he or she took the course as a Junior?
Make an A | Make an B | Make an C | Make an D | Make an F | Total | |
Sophomores | 0.058 | 0.101 | 0.142 | 0.092 | 0.047 | 0.44 |
Juniors | 0.055 | 0.082 | 0.102 | 0.071 | 0.030 | 0.34 |
Seniors | 0.014 | 0.023 | 0.080 | 0.063 | 0.040 | 0.22 |
Total | 0.127 | 0.206 | 0.324 | 0.226 | 0.117 | 1 |
P[ Junior | made a B or better ] = ( 0.055 + 0.082 ) / ( 0.127 + 0.206 )
P[ Junior | made a B or better ] = 0.137/0.333
P[ Junior | made a B or better ] = 0.4114
(d) Given that a particular student in Dr. Alan Math course is a Senior, what is the probability that he or she will make an A in the course?
Make an A | Make an B | Make an C | Make an D | Make an F | Total | |
Sophomores | 0.058 | 0.101 | 0.142 | 0.092 | 0.047 | 0.44 |
Juniors | 0.055 | 0.082 | 0.102 | 0.071 | 0.030 | 0.34 |
Seniors | 0.014 | 0.023 | 0.080 | 0.063 | 0.040 | 0.22 |
Total | 0.127 | 0.206 | 0.324 | 0.226 | 0.117 | 1 |
P[ make an A | Senior ] = 0.014/0.22
P[ make an A | Senior ] = 0.0636