Question

question 17
this table shows how many sophomores and juniors attended two school events.
what is the probability that a randomly chosen person from this group is a sophomore and attended the volleyball game? round your answer to two decimal places.
a. 0.31
b. 0.48
c. 0.56
d. 0.26

question 18
this table shows how many sophomores and juniors attended two school events. a student is selected randomly from this group.
what is the probability that the student attended the jazz concert, given that the student is a sophomore? round your answer to two decimal places.
a. 0.45
b. 0.55
c. 0.26
d. 0.49

question 19
the data give the average number of days in may that are clear and cloudy in two cities.
on a day in may, what is the probability that it is clear, given that you are in sacramento? explain how you found the answer, and round your answer to two decimal places.
a. 0.57, because 17 of the 30 days were clear
b. 0.28, because 17 of the 60 days were clear
c. 0.74, because 17 of the 23 days were clear
d. 0.20, because 6 of the 30 days were clear

Explanation:

Question 17

Step1: Identify target & total counts

Target count (sophomore + volleyball) = 42; Total people = 137

Step2: Calculate probability

$\text{Probability} = \frac{42}{137} \approx 0.31$

Question 18

Step1: Identify target & conditional counts

Target count (sophomore + jazz) = 35; Total sophomores = 77

Step2: Calculate conditional probability

$\text{Probability} = \frac{35}{77} \approx 0.45$

Question 19

Step1: Identify target & conditional counts

Target count (Sacramento + clear) = 17; Total days in Sacramento = 30

Step2: Calculate conditional probability

$\text{Probability} = \frac{17}{30} \approx 0.57$

Answer:

Question 17: A. 0.31
Question 18: A. 0.45
Question 19: A. 0.57, because 17 of the 30 days were clear