Fundamentals
What's the probability that a randomly selected student is in the Goldstein advisory?
(Round to three decimals)
15/387 = 0.039
When is Pi Day celebrated?
March 14th (3/14)
If A represents the event of randomly selecting a student who buys lunch, and the P(A) = 0.7. Find the complement of A.
A student who does not buy lunch
= 1- 0.7
0.3
A quick quiz consists of a true/false question followed by a multiple choice question with 4 possible answers. What is the probability of randomly guessing 2 correct answers?
1/8 or 0.125
What's the probability that a randomly selected student takes Statistics?
(Round to three decimals)
30/387 = 0.078
When is graduation day for IACS seniors (class of 2024)?
Saturday, June 1st
If A represents the event of randomly selecting a student who buys lunch, and the P(A) = 0.7. Find the probability of randomly selecting two students and finding that they both buy lunch.
0.7(0.7) = 0.49
In the 108th Congress, the Senate consists of 51 Republicans, 48 Democrats and 1 Independent. What is the probability of selecting 3 Senators and that those 3 Senators are Republican?
=(51/100)*(50/99)*(49/98)
=17/132 or 0.129
What's the probability that a randomly selected student takes Stats and is NOT in the Goldstein Advisory?
(Round to three decimals)
20/387 = 0.052
What number is represented by the letter D in Roman Numerals?
500
There is a 70% probability that a randomly selected student buys lunch. There is an 82% probability that a student is on time for school. There is a 90% probability that a student buys lunch OR is on time for school. Find the probability that a student buys lunch AND is on time for school.
P(A or B) = P(A) + P(B) - P(A and B)
0.90 = 0.70 + 0.82 - P(A and B)
P(A and B) = 1.52 - 0.90 = 0.62
0.62 or 62%
Two 6-sided dice are rolled. What is the probability that the sum of the two numbers on the dice will be 3?
(1,2) or (2,1) 2 ways out of 36 combinations
2/36 = 1/18 =
0.0556
On a multiple choice test with five possible answers for each question, what is the probability of answering the question correctly if you make a random guess?
1/5 or 0.2
If 2 students are randomly selected, what's the probability that they both take Stats?
(Round to three decimals)
(30/387)*(29/386) = 0.006
Name the best selling album of all time
Michael Jackson's Thriller
P(Likes chocolate) = 0.8
P(Likes chocolate or vanilla) = 0.94
P (Doesn't like vanilla) = 0.16
Find the probability that two people are randomly selected and the first person likes chocolate and the second person likes vanilla.
P (#1 Likes chocolate AND #2 Likes vanilla)
= 0.8 (0.84)
0.672
If a person is randomly selected, find the probability that his or her birthday is not in May. Ignore leap years.
334/365 or 0.915
In a couple had 3 children, what is the probability that among the three children, there are exactly 2 girls?
3/8 or 0.375
Are the events taking Stats and being in the Goldstein Advisory independent? Prove using at least one test of independence.
(Round to three decimals)
No, they are dependent events.
P(A) does not equal P(A|B)
P(Stats) =30/387 = 0.078
P(Stats|Goldstein Adv) = 10/15 = 0.667
0.078 does not equal 0.667
According to the Guinness Book of World Records, what is the largest chocolate bar ever created (in terms of weight)?
12,770 pounds, 4.48 ounces
(5,792.5 kg) in the UK in October 2011
P(Likes chocolate) = 0.8
P(Likes chocolate or vanilla) = 0.94
P (Doesn't like vanilla) = 0.16
Find the P(Likes chocolate and vanilla)
P(Likes vanilla) = 1 - 0.16 = 0.84
P(C or V) = P(C) + P(V) - P(C and V)
0.94 = 0.8 + 0.84 - P(C and V)
P(C and V) = 1.64 - 0.94 = 0.7
There is 0.2 probability of guessing correctly on any given problem of a multiple choice test. Given a m/c test with 10 questions, what is the probability that a person guesses correctly on AT LEAST one question?
P(all incorrect) = (0.8)^10 = 0.107374...
P(at least one correct) = 1 - 0.107374...
0.893