Session:B |

Mathematical Phrases, Symbols, and Formulas

Introductory Business Statistics | Leadership Development – Micro-Learning Session

Rice University 2020 | Michael Laverty, Colorado State University Global Chris Littel, North Carolina State University| https://openstax.org/details/books/introductory-business-statistics

English Phrases Written Mathematically

When the English says: Interpret this as:
X is at least 4. X ≥ 4
The minimum of X is 4. X ≥ 4
X is no less than 4. X ≥ 4
X is greater than or equal to 4. X ≥ 4
X is at most 4. X ≤ 4
The maximum of X is 4. X ≤ 4
X is no more than 4. X ≤ 4
X is less than or equal to 4. X ≤ 4
X does not exceed 4. X ≤ 4
X is greater than 4. X > 4
X is more than 4. X > 4
X exceeds 4. X > 4
X is less than 4. X < 4
There are fewer X than 4. X < 4
X is 4. X = 4
X is equal to 4. X = 4
X is the same as 4. X = 4
X is not 4. X ≠ 4
X is not equal to 4. X ≠ 4
X is not the same as 4. X ≠ 4
X is different than 4. X ≠ 4
Table B1

Symbols and Their Meanings

Chapter (1st used) Symbol Spoken Meaning
Sampling and Data         −−−−√

         

The square root of same
Sampling and Data π

 

Pi 3.14159… (a specific number)
Descriptive Statistics Q1 Quartile one the first quartile
Descriptive Statistics Q2 Quartile two the second quartile
Descriptive Statistics Q3 Quartile three the third quartile
Descriptive Statistics IQR interquartile range Q3 – Q1 = IQR
Descriptive Statistics x

 

x-bar sample mean
Descriptive Statistics μ

 

mu population mean
Descriptive Statistics s s sample standard deviation
Descriptive Statistics s2

2 

s squared sample variance
Descriptive Statistics σ

 

sigma population standard deviation
Descriptive Statistics σ2

2 

sigma squared population variance
Descriptive Statistics Σ

 

capital sigma sum
Probability Topics {}

{} 

brackets set notation
Probability Topics S

 

S sample space
Probability Topics A

 

Event A event A
Probability Topics P(A)

() 

probability of A probability of A occurring
Probability Topics P(A|B)

(A|B) 

probability of A given B prob. of A occurring given B has occurred
Probability Topics P(AB)

() 

prob. of A or B prob. of A or B or both occurring
Probability Topics P(AB)

() 

prob. of A and B prob. of both A and B occurring (same time)
Probability Topics A A-prime, complement of A complement of A, not A
Probability Topics P(A‘) prob. of complement of A same
Probability Topics G1 green on first pick same
Probability Topics P(G1) prob. of green on first pick same
Discrete Random Variables PDF prob. density function same
Discrete Random Variables X X the random variable X
Discrete Random Variables X ~ the distribution of X same
Discrete Random Variables

 

greater than or equal to same
Discrete Random Variables

 

less than or equal to same
Discrete Random Variables = equal to same
Discrete Random Variables not equal to same
Continuous Random Variables f(x) f of x function of x
Continuous Random Variables pdf prob. density function same
Continuous Random Variables U uniform distribution same
Continuous Random Variables Exp exponential distribution same
Continuous Random Variables f(x) = f of x equals same
Continuous Random Variables m m decay rate (for exp. dist.)
The Normal Distribution N normal distribution same
The Normal Distribution z z-score same
The Normal Distribution Z standard normal dist. same
The Central Limit Theorem X

 

X-bar the random variable X-bar
The Central Limit Theorem μx

 

mean of X-bars the average of X-bars
The Central Limit Theorem σx

 

standard deviation of X-bars same
Confidence Intervals CL confidence level same
Confidence Intervals CI confidence interval same
Confidence Intervals EBM error bound for a mean same
Confidence Intervals EBP error bound for a proportion same
Confidence Intervals t Student’s t-distribution same
Confidence Intervals df degrees of freedom same
Confidence Intervals tα2

2 

student t with α/2 area in right tail same
Confidence Intervals p

 

p-prime sample proportion of success
Confidence Intervals q

 

q-prime sample proportion of failure
Hypothesis Testing H0

0 

H-naught, H-sub 0 null hypothesis
Hypothesis Testing Ha

 

H-aH-sub a alternate hypothesis
Hypothesis Testing H1

1 

H-1, H-sub 1 alternate hypothesis
Hypothesis Testing α

 

alpha probability of Type I error
Hypothesis Testing β

 

beta probability of Type II error
Hypothesis Testing X1X2¯¯¯¯¯

12¯ 

X1-bar minus X2-bar difference in sample means
Hypothesis Testing μ1μ2

12 

mu-1 minus mu-2 difference in population means
Hypothesis Testing P1P2

12 

P1-prime minus P2-prime difference in sample proportions
Hypothesis Testing p1p2

12 

p1 minus p2 difference in population proportions
Chi-Square Distribution X2

2 

Ky-square Chi-square
Chi-Square Distribution O

 

Observed Observed frequency
Chi-Square Distribution E

 

Expected Expected frequency
Linear Regression and Correlation y = a + bx y equals a plus b-x equation of a straight line
Linear Regression and Correlation yˆ

^ 

y-hat estimated value of y
Linear Regression and Correlation r

 

sample correlation coefficient same
Linear Regression and Correlation ε

 

error term for a regression line same
Linear Regression and Correlation SSE Sum of Squared Errors same
F-Distribution and ANOVA F F-ratio F-ratio
Table B2 Symbols and their Meanings

Formulas

Symbols you must know
Population Sample
N

 

Size n

 

μ

 

Mean x––

_ 

σ2

2 

Variance s2

2 

σ

 

Standard deviation s

 

p

 

Proportion p

 

Single data set formulae
Population Sample
μ=E(x)=1NNi=1(xi)

=()=1=1() 

Arithmetic mean x=1nni=1(xi)

=1=1() 

Geometric mean x˜=(i=1nXi)1n

~=(=1)1 

Q3=3(n+1)4

3=3(+1)4Q1=(n+1)4

1=(+1)4 

Inter-quartile range
IQR=Q3Q1 =31 
Q3=3(n+1)4

3=3(+1)4Q1=(n+1)4

1=(+1)4 

σ2=1NNi=1(xiμ)2

2=1=1()2 

Variance s2=1nni=1(xix––)2

2=1=1(_)2 

Single data set formulae
Population Sample
μ=E(x)=1NNi=1(mifi)

=()=1=1(·) 

Arithmetic mean x=1nni=1(mifi)

=1=1(·) 

Geometric mean x˜=(i=1nXi)1n

~=(=1)1 

σ2=1NNi=1(miμ)2fi

2=1=1()2· 

Variance s2=1nni=1(mix––)2fi

2=1=1(_)2· 

CV=σμ100

=·100 

Coefficient of variation CV=sx––100

=_·100 

Table B3
Basic probability rules
P(AB)=P(A|B)P(B)

()=(|)·() 

Multiplication rule
P(AB)=P(A)+P(B)P(AB)

()=()+()() 

Addition rule
P(AB)=P(A)P(B)

()=()·() or P(A|B)=P(A)

(|)=() 

Independence test
Hypergeometric distribution formulae
nCx=(nx)=n!x!(nx)!

=()=!!()! 

Combinatorial equation
P(x)=(Ax)(NAnx)(Nn)

()=()()() 

Probability equation
E(X)=μ=np

()== 

Mean
σ2=(NnN1)np(q)

2=(1)() 

Variance
Binomial distribution formulae
P(x)=n!x!(nx)!px(q)nx

()=!!()!() 

Probability density function
E(X)=μ=np

()== 

Arithmetic mean
σ2=np(q)

2=() 

Variance
Geometric distribution formulae
P(X=x)=(1p)x1(p)

(=)=(1)1() 

Probability when x

 is the first success.

Probability when x

 is the number of failures before first success

P(X=x)=(1p)x(p)

(=)=(1)() 

μ=1p

=1 

Mean Mean μ=1pp

=1 

σ2=(1p)p2

2=(1)2 

Variance Variance σ2=(1p)p2

2=(1)2 

Poisson distribution formulae
P(x)=eμμxx!

()=! 

Probability equation
E(X)=μ

()= 

Mean
σ2=μ

2= 

Variance
Uniform distribution formulae
f(x)=1ba

()=1 for axb

 

PDF
E(X)=μ=a+b2

()==+2 

Mean
σ2=(ba)212

2=()212 

Variance
Exponential distribution formulae
P(Xx)=1emx

()=1 

Cumulative probability
E(X)=μ=1m

()==1 or m=1μ

=1 

Mean and decay factor
σ2=1m2=μ2

2=12=2 

Variance
Table B4
The following page of formulae requires the use of the “Z“, “t“, “χ22” or “F” tables.
Z=xμσ= Z-transformation for normal distribution
Z=xnpnp(q)=() Normal approximation to the binomial
Probability (ignores subscripts)
Hypothesis testing
Confidence intervals
[bracketed symbols equal margin of error]
(subscripts denote locations on respective distribution tables)
Zc=x¯μ0σn=¯0 Interval for the population mean when sigma is known
x¯±[Z(α/2)σn]¯±[(/2)]
Zc=x¯μ0sn=¯0 Interval for the population mean when sigma is unknown but n>30>30
x¯±[Z(α/2)sn]¯±[(/2)]
tc=x¯μ0sn=¯0 Interval for the population mean when sigma is unknown but n<30<30
x¯±[t(n1),(α/2)sn]¯±[(1),(/2)]
Zc=pp0p0q0n=000 Interval for the population proportion
p±[Z(α/2)pqn−−−√]±[(/2)]
tc=dδ0sdn=0 Interval for difference between two means with matched pairs
d±[t(n1),(α/2)sdn]±[(1),(/2)] where sd is the deviation of the differences
Zc=(x1x2)δ0σ21n1+σ22n2=(12)0121+222 Interval for difference between two means when sigmas are known
(x1x2)±[Z(α/2)σ21n1+σ22n2−−−−−−−√](12)±[(/2)121+222]
tc=(x¯1x¯2)δ0((s1)2n1+(s2)2n2)=(¯1¯2)0((1)21+(2)22) Interval for difference between two means with equal variances when sigmas are unknown
(x¯1x¯2)±[tdf,(α/2)((s1)2n1+(s2)2n2)−−−−−−−−−−−−√](¯1¯2)±[,(/2)((1)21+(2)22)] where df=((s1)2n1+(s2)2n2)2(1n11)((s1)2n1)+(1n21)((s2)2n2)=((1)21+(2)22)2(111)((1)21)+(121)((2)22)
Zc=(p1p2)δ0p1(q1)n1+p2(q2)n2=(12)01(1)1+2(2)2 Interval for difference between two population proportions
(p1p2)±[Z(α/2)p1(q1)n1+p2(q2)n2−−−−−−−−−−−−√](12)±[(/2)1(1)1+2(2)2]
χ2c=(n1)s2σ202=(1)202 Tests for GOF, Independence, and Homogeneity
χ2c=Σ(OE)2E2=Σ()2where O = observed values and E = expected values
Fc=s21s22=1222 Where s2112 is the sample variance which is the larger of the two sample variances
The next 3 formulae are for determining sample size with confidence intervals.
(note: E represents the margin of error)
n=Z2(a2)σ2E2=(2)222
Use when sigma is known
E=x¯μ=¯
n=Z2(a2)(0.25)E2=(2)2(0.25)2
Use when p is unknown
E=pp=
n=Z2(a2)[p(q)]E2=(2)2[()]2
Use when p is unknown
E=pp=
Table B5
Simple linear regression formulae for y=a+b(x)=+()
r=Σ[(xx¯)(yy¯)]Σ(xx¯)2*Σ(yy¯)2=SxySxSy=SSRSST−−−−√=Σ[(¯)(¯)]Σ(¯)2*Σ(¯)2== Correlation coefficient
b=Σ[(xx¯)(yy¯)]Σ(xx¯)2=SxySSx=ry,x(sysx)=Σ[(¯)(¯)]Σ(¯)2==,() Coefficient b (slope)
a=y¯b(x¯)=¯(¯) y-intercept
s2e=Σ(yiyˆi)2nk=Σi=1ne2ink2=Σ(^)2=Σ=12 Estimate of the error variance
Sb=s2e(xix¯)2=s2e(n1)s2x=2(¯)2=2(1)2 Standard error for coefficient b
tc=bβ0sb=0 Hypothesis test for coefficient β
b±[tn2,α/2Sb]±[2,/2] Interval for coefficient β
yˆ±[tα/2*se(1n+(xpx¯)2sx−−−−−−−−−√)]^±[/2*(1+(¯)2)] Interval for expected value of y
yˆ±[tα/2*se(1+1n+(xpx¯)2sx−−−−−−−−−−−−√)]^±[/2*(1+1+(¯)2)] Prediction interval for an individual y
ANOVA formulae
SSR=Σi=1n(yˆiy¯)2=Σ=1(^¯)2 Sum of squares regression
SSE=Σi=1n(yˆiy¯i)2=Σ=1(^¯)2 Sum of squares error
SST=Σi=1n(yiy¯)2=Σ=1(¯)2 Sum of squares total
R2=SSRSST2= Coefficient of determination
Table B6
The following is the breakdown of a one-way ANOVA table for linear regression.
Source of variation Sum of squares Degrees of freedom Mean squares F-ratio
Regression SSR 11 or k11 MSR=SSRdfR= F=MSRMSE=
Error SSE nk MSE=SSEdfE=
Total SST n11
Table B7

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