Drawing Inferences, Stats and Probability

Suppose that A and B are two independent events with P(A) = .2 and P(B) = .4. 
P(A∩B^C) is

• .08

• .12

• .52

• .60

At a California college, 19% of the students speak Spanish, 7% speak French, and 4% speak both languages.  A student is chosen at random from the college.  What is the probability that the student speaks Spanish if she speaks French?

• 0.220

• 0.211

• 0.040

• 0.571

What is the probability that a student does play a sport given they do not play an instrument? 

• .2

• .2222

• .10

• .5

Find the Z-score.

Mean = 22

Standard Deviation: 3.1

x = 29

• 2.26

• 16.45

• -2.26

• 1.26

In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. Approximately 95% of molds filled by this machine will hold weights in what interval?

• 1084 to 1216 pounds 

• 1106 to 1150 pounds 

• 1106 to 1194 pounds 

• 1128 to 1172 pounds

Steve took his math test and scored an 88. If the class average was a 78 with a standard deviation of 5, what percent of students earned a grade that was higher than Steve's grade?

• 97.5%

• 93%

• 5%

• 2.5%

• 15.87%

• 15.39%

• 9.68%

• 84.61%

In a drawer, there are 6 white socks, 4 black socks, and 2 brown socks. You pick out a sock, replace it, then pick out a 2nd sock. What is the probability that you will pick a brown, then black sock?

• 1/11

• 1/18

• 1/36

• 2/33

A jar contains 2 pink, 6 red, and 4 blue marbles. If you pick one marble without looking, what is the probability that the marble you pick will be red or blue?

• 5/6

• 1/2

• 1/3

• 1/6

The diagram shows the sports played by 80 students.

If a student is picked at random, what is the probability that they play football?

• ⁶⁶/₈₀

• ⁴/₈₀

• ¹⁸/₈₀

• ⁴⁹/₈₀