Introduction Statistics
Customer satisfaction is an example of what type of variable in terms of level of measurement?
Ordinal level
In Steve's data, the mean is larger than the median. What does this tell you about the distribution?
The distribution is positively skewed (right-skewed).
If two events are independent, how do you find the probability of their joint occurrence?
Multiply their probabilities together
Name two characteristics of a discrete random variable
Sum of probabilities of all possible outcomes is 1
The probability of a particular outcome is between 0 and 1
All outcomes are mutually exclusive
In 2026 I was the staff advisor for this event in BA.
BAFO
What type of variable and its level of measurement is the time it takes to travel to Ngee Ann?
Quantitative, continuous; ratio level
Patricia wants to compare the variation between two samples involving different quantitative variables with different measurement scales. What measurement would be best for this comparison?
Use a coefficient of variation
If P(A)=0.4, P(B)=0.7P and P(A and B)=0.25, what can you conclude about the events A and B?
The events are non-mutually exclusive.
A wine sales business has found that, on average, each customer buys a rare bottle of wine with a probability of 0.04. If the store serves 60 customers in a day, what is the probability that exactly 2 customers will buy a rare bottle of wine?
0.2654
Famous football player from Mr. Harry's country of birth.
Luka Modric
Steve, a personal chef, analysed a sample of 17 dishes from his menu to record their calorie content. Based on this data, how many classes are recommended for constructing a frequency table?
Five classes
Sarah claims, "Variance is always greater than the standard deviation because variance is the square of the standard deviation." Tom disagrees, saying, "The standard deviation can be larger than the variance." Who is correct, and why?
Tom is correct
Jessica sources 400 vinyl records each month from Golf Co., Mitski Inc., and Twilight Co. She reviews the defective records from these suppliers to make an informed business decision. Given the following data, what is the probability that a random record is defective?
Suppliers, Defective Rate (%), Order Quantity
Golf Co. (2.3) (150)
Mitski Inc. (1.1) (200)
Twilight Co. (3.1) (50)
0.018
80 registrants have signed up for the Art Festive event. Each registrant is required to choose one time slot to attend from the options: 9am, 11am, 1pm, or 3pm. Is this scenario a binomial experiment? Explain why.
No. Too many options.
My dog Phoebe is a mix of two breeds. Name one.
Poodle
Cavalier King Charles Spaniel
Given Steve's sample data of calorie content from 17 dishes:
178, 211, 198, 186, 157, 220, 163, 209, 189, 197, 168, 175, 219, 211, 205, 162, 233.
What class interval should be used to create a frequency table?
Interval length = (Max. – Min.)/ Classes = (233 – 157)/5 = 15.2 = 16
Calculate the median of Steve's data set:
178, 211, 198, 186, 157, 220, 163, 209, 189, 197, 168, 175, 219, 211, 205, 162, 233.
Median: 197
Jessica sources 400 vinyl records each month from Golf Co., Mitski Inc., and Twilight Co. She reviews the defective records from these suppliers to make an informed business decision. What is the probability that a record was produced by Mitski Inc., given that it was defective?
Suppliers, Defective Rate (%), Order Quantity
Golf Co. (2.3) (150)
Mitski Inc. (1.1) (200)
Twilight Co. (3.1) (50)
0.3056
The probability of a baker accidentally making a mistake on a recipe is 0.05. What is the probability that the baker does not make a mistake in 15 recipes?
0.4633
In my previous jobs, I used to (mostly) trade these financial instruments?
Bonds
Organize the following calorie data into a frequency distribution table:
178, 211, 198, 186, 157, 220, 163, 209, 189, 197, 168, 175, 219, 211, 205, 162, 233.
Interval Frequency
157–173 (4)
173–189 (3)
189–205 (3)
205–221 (6)
221–237 (1)
Using the frequency table constructed earlier in "Intro to Statistics" for $600, calculate the mean.
194.1765
Jessica sources 400 vinyl records each month from Golf Co., Mitski Inc., and Twilight Co. She reviews the defective records from these suppliers to make an informed business decision. What is the probability that a record was produced by Mitski Inc. or Twilight Co., given that it was defective?
Suppliers, Defective Rate (%), Order Quantity
Golf Co. (2.3) (150)
Mitski Inc. (1.1) (200)
Twilight Co. (3.1) (50)
0.5208
Customers arrive at a bakery at random at an average rate of 8 per hour. What is the probability that, during any 80-minute period, the number of customers arriving at the bakery is more than 1?
0.9997
What's my alma mater (aka uni i went to)?
University of Chicago