Statistics Formula Flashcards Preview

A Level Maths > Statistics Formula > Flashcards

Flashcards in Statistics Formula Deck (17):
1

What is the formula to work out the value of k in a histogram?

k = (area of bar)/freq

2

What is the formula for linear interpolation?

linear interpolation = Lower bound of class + (freq into class/freq)Class width

3

What is the formula for frequency density in a histogram?

freq density = freq/class width

4

What is the formula for variance in discrete data?

((∑x^2/n) - (∑x/n)^2))

5

What is the formula for Standard deviation?

√(variance)

6

What is the formula to work out IQR?

Q3 - Q1

7

What is the formula to work out Q1?

n/4

8

What is the formula to work out Q3?

3n/4

9

What is the formula to work out the area of a bar in a histogram?

Area of bar = k x freq

10

What is the formula to work out frequency in a histogram?

Freq = freq density x class width

11

What is the formula in terms of quartiles to show that there is a positive skewness?

Q2 - Q1 < Q3 - Q2

12

What is the formula in terms of quartiles to show that there is a symmetrical skewness?

Q2 - Q1 = Q3 - Q2

13

What is the formula in terms of quartiles to show that there is a negative skewness?

Q2 - Q1 > Q3 - Q2

14

What is the addition rule in probability?

P(AuB) = P(A) + P(B) - P(AnB)

15

What is the multiplication rule in probability?

P(AnB) = P(AIB) x P(B)

or

P(AnB) = P(BIA) x P(A)

16

What is the formula for variance in discrete random variables?

Var = (EX^2) - ((EX)^2))

17

X~N(𝛍,𝛔^2)
In normal distribution what is the formula to transform X into Z? and what does 𝛍 and 𝛔 stand for?

Z = (X - 𝛍)/ 𝛔

𝛍 = mean
𝛔 = standard deviation