Statistics & Probability Cheat Sheet

Statistics and Probability
Statistics and Probability
Khan Academy

Takeaways from the Statistics and Probability course.

Individuals - the people or things described by a data set.  

Variables -characteristics of the individuals that we measure or observe.

Categorical variables take on values that are labels or categories

Quantitative variables take on numerical values.

Mean: (Average) Add together all the numbers in the data set, then divide by the amount of numbers.
Median: Put the numbers in the data set in numerical order, then find the middle number. If the set has an even amount of numbers, find the two middle numbers, then find the mean of them.
Mode: Count the number of repeating numbers in the data set. The number that appears the most is the mode.

Absolute and Relative Frequency Tables

Absolute Frequency Table
Absolute Frequency Table

Relative Frequency Table
Relative Frequency Table
What do we know?
  • 48 Squares are 65.75% of the total.
  • ∴ the total number of tiles (Z) has to be:
    • Z * .6575 = 48
    • Z = 48/.6575 = 73
    • Total Tiles = 73
  • Total number of rectangles has to be 25.
    • We can verify this 2 ways:
    • 73 – 48 = 25
    • 34.25% of 73 = 25

This is enough information to complete the Absolute Frequency table.

To solve for in the Relative Frequency table, all we have to figure out is what percentage of off-white tiles were rectangles:

there were 33 off-white tiles and 10 of them were rectangles.
∴ x = 10/33 ≈ 0.303 = 30.3%
  • Individuals are the Rooms
  • Variables
    • seating capacity
    • hire cost
    • has projector
    • is accessible
  • Quantitative Variables
    • seating capacity
    • hire cost


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