Question

Please use excel and show the work.

Below is a frequency table for midterm exam scores

Scores Number of students

90 and up 5

80-89 12

70-79 40

60-69 18

50-59 13

40-49 6

30-39 6

A.) Construct a frequency table that displays probabilities of occurrence for each class and cumulative probabilities.

B.) What is the probability that a random student picked will have a score of at least 90? Less than 90?  

c.) What is the probability that a random student picked will have a score of at least 60?

d.) What is the probability that a random student picked will have a score of more than 39 and less than 60?

Answer 1

(A)

Class Interval	Probability of occurrence	Cumulative Probability
90 and up	5/100=0.05	0.05
80 - 89	12/100=0.12	0.17
70 - 79	40/100=0.40	0.57
60 - 69	18/100=0.18	0.75
50 - 59	13/100=0.13	0.88
40 - 49	6/100=0.06	0.94
30 - 39	6/100=0.06	1.00

(B)

(i)
P(X90) = 0.05

(ii)

P(X<90) = 0.12+0.40+0.18+0.13+0.06+0.06 = 0.95

(c)
P(X60)=0.05+0.12+0.40+0.18=0.75

(d)

P(39<X<60)= 0.06+0.13=0.19