formulas Flashcards
formula for independent events?
P (A and B) = P (A) x P (B)
formula for the general addition law?
P (A or B) = P (A) + P (B) - P (A and B)
formula for mutually exclusive events?
P (A or B) = P (A) + P (B)
formula for event A not happening?
1-P (event A happens) or P (Not A) = 1 - P (A)
formula for finding an estimated mean from a grouped set of data?
mean=total(frequency x midpoint)/total frequency
formula for estimated mean from a grouped set of data?
-make a new column called f x midpoint
-sum of f x midpoint / frequency
formula for geometric mean?
n x square root of value 1 x value 2 x value 3 etc
formula for finding lower quartile?
1/4(n+1)th value
how to figure IQR?
upper quartile-lower quartile
formula for weighted mean?
total(value x weight)/ total(weight)
formula for probability of an event?
number of successful outcomes/ total number of possible outcomes
formula for estimated probability?
number of trials with successful outcomes/ total number of trials
formula for risk of an event?
number of trials in which event happens/total number of trials
formula for expected frequency?
p(A)x number of trials
formula for conditional probability?
P(A/B) x P(B)
formula for conditional probability of B given A is?
P(B/A)=P(A and B) / P(A)
formula for conditional probability of B given A from a venn diagram?
P(B/A)=number of outcomes in A&B/number of outcomes in A
how to figure out the mean from a frequency table?
-make a cf table
1/2 (n+1)- look for that number then find the frequency
how to find averages from grouped data?
-make a cf table
-1/2 x n for the median
-the number in the c.f table that is just above it is the median
