Chapter 5 Basic Statistics
5.1 Definitions
population - all existing samples
sample - subset of statistical population
simple random sample - random subset
stratified sample - fist clustering, than random sample from
cluster sample - random choosing from several existing clusters
variables - discret, continuous, ordinal (ранговая)
5.2 Probability
A standard French-suited deck of playing cards contains 52 cards; 13 each of hearts (♥), spades (♠), clubs (♦), and diamonds (♣). Assuming that you have a well-shuffled deck in front of you, the probability of drawing any given card is 1/52 ≈ 1.92%.
Calculate the probability of drawing any of the four aces! That is, calculate the probability of drawing 🂡 or 🂱 or 🃁 or 🃑 using the sum rule and assign it to prob_to_draw_ace.
# Calculate the probability of drawing any of the four aces
<- 1/52 + 1/52 + 1/52 + 1/52 prob_to_draw_ace
Cards and the product rule
Again, assuming that you have a well-shuffled deck in front of you, the probability of drawing any given card is 1/52 ≈ 1.92% . The probability of drawing any of the four aces is 1/52 + 1/52 + 1/52 + 1/52 = 4/52. Once an ace has been drawn, the probability of picking any of the remaining three is 3/51. If another ace is drawn the probability of picking any of the remaining two is 2/50, and so on.
Use the product rule to calculate the probability of picking the four aces in a row from the top of a well-shuffled deck and assign it to prob_to_draw_four_aces.
# Calculate the probability of picking four aces in a row
<- 4/52 * 3/51 * 2/50 * 1/49 prob_to_draw_four_aces