Interpreting Data
What is the difference between joint and marginal frequencies?
Joint frequency is the combination of two conditions whereas marginal frequencies are the subtotals between individual categories
What are the two ways to make a statistical inference?
Estimation and Hypothesis Testing
You have a bag of 30 candies, consisting of 15 chocolate bars, 10 gummy worms, and 5 lollipops. If you randomly pick a candy from the bag, what is the probability that it's a chocolate bar?
50%
What is a fair system of decision-making or when is a game fair?
One where each outcome is equally likely or when the expected value is equal to zero
The 2000's most popular Halloween costume was this yellow character who lived in a pineapple under the sea.
Spongebob Squarepants
Find the error in the following line of code: Cor(Students, GPA)
the c in Cor should be lowercase
A paranormal investigator claims the average temperature inside a supposedly haunted house is 66º F. To test this claim, the owner of the house measures the temperature inside the house on 20 different nights. The sample mean temperature is found to be 68º F, with a sample standard deviation of 3º. The owner then performs a hypothesis test to a 98% significance level. What should the p-value be so the owner can reject the investigator’s claim?
Less than 0.02
You're at a Halloween costume party with 30 guests. Among them, 18 are wearing costumes, and 12 are not. If you select a random guest, what is the probability that they are wearing a costume?
60%
Corey and Kaitlin both want to be Barbie for Halloween, but they can't. Is this a fair way to decide who gets to be Barbie? Corey pulls out his graphing calculator. He commands the calculator to generate a random integer from 1 to 15 (inclusive). If the number is 7 or below, Corey gets to be Barbie. If the number is 9 or above, Kaitlin gets to be Barbie. If the number is 8, they generate a new number and repeat.
It is fair.
Corey success: 7/15, Kaitlin success: 7/15, Retry: 1/15
(Retry does not have to be equal because it does not affect the outcome in either's favor)
The most Popular 1980's Halloween costume was this moonwalking popstar with his red leather jacket and his one white glove.
Michael Jackson
How do you compare the spread of a data set?
Interquartile Range and Standard Deviation
A neighborhood group of moms claims that the average number of trick-or-treaters visiting their houses on Halloween is 50. They select 40 random houses in their neighborhood and find a sample mean of 51 trick-or-treaters with a true standard deviation of 7. Find the test statistic (hint: z-test).
0.9035
You're trick-or-treating in a neighborhood known for its diverse candy distribution. You visit three houses. House A gives out candy bars 40% of the time, House B gives out gummy candies 60% of the time, and House C gives out a toy 20% of the time. If you visit the houses in the order A, B, C, what is the probability that you'll receive a toy from House C given that you've already received gummy candies from House B?
20%
Define Expected Utility
How much value a potential gain or loss has to the individual.
The #1 Halloween costume of the 70's was this character who helped Dorothy get home while receiving his own heart.
The Tin Man
Give the correct line of code for a histogram showing Average GPA frequency.
hist(GPA)
Michael Myers claims that he can carve a jack-o’-lantern, on average, in 80 seconds. Pennywise doesn’t believe him, so he has Michael carve 100 pumpkins. Taking a random sample of 30 of the carving times, he finds a sample mean of 76 seconds per carving, with a standard deviation of 9 seconds. State your hypotheses and test statistic value.
H0: µ = 80 Ha: µ ≠ 80
z = -2.434
In a dark and spooky forest, you encounter a black cat, a ghost, and a vampire. Each has a distinct probability of leading you deeper into the forest. The black cat leads you further 20% of the time, the ghost 30% of the time, and the vampire 40% of the time. If you follow one of them and find yourself deeper in the forest, what is the probability that you followed the black cat given that you didn't follow the vampire?
20%
Decide the most logical choice between these two:
Option A: Coin flip, where heads wins you $1,000 and tails wins you nothing
Option B: Guaranteed $400
Option A EU: 0.5 * U(10) + 0.5 * U(0) = 50 + 0 = 50
Option B EU: 1.0 * U(4) = 60
60>50 so Option B
The most popular Halloween Costume of the 1960's was this little boy who was always causing trouble for his neighbor, Mr. George Wilson.