Question

The table above summarizes the grades of a previous STAT 2110 exam between a morning and afternoon section of the course 18 16 34 10 13 23 Total 85 84 169 24 Morning Afternoon Total 19 21 40 10 48 24 (Round all probabilities to four decimals) a) If a student is from the afternoon section, what's the probability he or she earned an A? b) The DF rate is reported to the Dean after each exam. (The DF rate is the percent of students who received a D or F). What number was reported to the Dean for this exam? c) What's the probability of a student receiving a B and being in the morning section? +) the morning section d) Receiving an A is ( (Click to select)

Answer 1

a) For finding the probability of student earning an A grade in afternoon section, Probability

$\small P =\frac {( \#\ students\ earning \ A\ in\ afternoon\ section)} {(\#\ students\ in\ afternoon\ section)} = \frac{21}{84} = {0.25}$

b) For finding DF (student who received D or F) rate (percentage) reported to Dean =

$\small \frac{( \#\ students\ earning \ D\ or\ F)} {(\#\ total \ students\ in\ exam)} = \frac{(24 + 23)}{169} \ * 100 = \frac{47}{169} \ * 100 = 27.81 \%$

c) For finding the probability of student earning a B grade in morning section, Probability

$\small P =\frac {( \#\ students\ earning \ B\ in\ morning\ section)} {(\#\ students\ in\ morning\ section)} = \frac{24}{85} = {0.2823}$

d) For finding the probability of student earning an A grade in morning section, Probability

$\small P =\frac {( \#\ students\ earning \ A\ in\ morning\ section)} {(\#\ students\ in\ morning\ section)} = \frac{19}{85} = {0.2235}$

(note :- # indicates number of )