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