formulas

Question 1

formula for independent events?

Answer 1

P (A and B) = P (A) x P (B)

Question 2

formula for the general addition law?

Answer 2

P (A or B) = P (A) + P (B) - P (A and B)

Question 3

formula for mutually exclusive events?

Answer 3

P (A or B) = P (A) + P (B)

Question 4

formula for event A not happening?

Answer 4

1-P (event A happens) or P (Not A) = 1 - P (A)

Question 5

formula for finding an estimated mean from a grouped set of data?

Answer 5

mean=total(frequency x midpoint)/total frequency

Question 6

formula for estimated mean from a grouped set of data?

Answer 6

-make a new column called f x midpoint
-sum of f x midpoint / frequency

Question 7

formula for geometric mean?

Answer 7

n x square root of value 1 x value 2 x value 3 etc

Question 8

formula for finding lower quartile?

Answer 8

1/4(n+1)th value

Question 9

how to figure IQR?

Answer 9

upper quartile-lower quartile

Question 10

formula for weighted mean?

Answer 10

total(value x weight)/ total(weight)

Question 11

formula for probability of an event?

Answer 11

number of successful outcomes/ total number of possible outcomes

Question 12

formula for estimated probability?

Answer 12

number of trials with successful outcomes/ total number of trials

Question 13

formula for risk of an event?

Answer 13

number of trials in which event happens/total number of trials

Question 14

formula for expected frequency?

Answer 14

p(A)x number of trials

Question 15

formula for conditional probability?

Answer 15

P(A/B) x P(B)

Question 16

formula for conditional probability of B given A is?

Answer 16

P(B/A)=P(A and B) / P(A)

Question 17

formula for conditional probability of B given A from a venn diagram?

Answer 17

P(B/A)=number of outcomes in A&B/number of outcomes in A

Question 18

how to figure out the mean from a frequency table?

Answer 18

-make a cf table
1/2 (n+1)- look for that number then find the frequency

Question 19

how to find averages from grouped data?

Answer 19

-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