**What am I testing?**

Numerical Data

Means

Categorical Data

Proportions

**How many?**

**1**

**2**

**How many?**

**lots**

Numerical

x Categorical

A moving mean

Numerical

x Numerical

Categorical

x Categorical

**1**

**2**

**lots**

Is it normal?

Is it normal?

Is it normal?

Is it normal?

Yes, it says

it's normal

No but

n>30

No and

n is small

By the Central Limit Theorem

You are stuck.

Go ask a statistician

for a bootstrapping

technique

Do you know the population standard deviation: sigma?

Or was the standard deviation given as part of a sample: s?

The standard deviation

was known before the

sample was taken

The standard deviation

was calculated after a

sample was chosen

Sigma

S

One sample z-test for a mean

One sample t-test for a mean

No and

n is small

You are stuck.

Go ask a statistician

for a resampling

technique

Yes, it says

it's normal

No but n1>30

and n2>30

By the Central Limit Theorem

Are the samples independent

Or is this matched pairs?

Matched Pairs

Matched Pairs test for a difference of means

Does each group have the

same standard deviation?

It doesn't say so

Yes, sigma1 = sigma2

Two sample independent t-test for a difference in means

Two sample pooled t-test for a difference in means

No,

np<15 or

n(1-p)<15

Yes,

np>15 and

n(1-p)>15

One sample z-test for a proportion

By the Central Limit Theorem

You are stuck.

Go ask a statistician

for Fisher's Exact Test

Yes,

n1p1>15 and n1(1-p1)>15

and

n2p2>15 and n2(1-p2)>15

Two sample z-test for a difference in proportions

By the Central Limit Theorem

No,

np<15 or n(1-p)<15

for at least one of the samples

You are stuck.

Go ask a statistician

for Fisher's Exact Test

Do you expect at least

5 observations

in every category?

No, the sample

is not that large

You are stuck.

Try consolidating categories

Or as a statistician for a

cluster analysis

Do you know the proportions

you expect to get?

Yes, at least

Yes

No, I am testing for

Independence

Chi-squared Goodness of Fit test

Chi-squared test of Independence

Can you tell from the residuals

1) Linear

2) Normal

3) Constant Variance

4) Independent

5) Residuals average 0

I do not see any pattern

in the residuals

You are stuck.

Go ask a statistician

for a generalized

non-linear model

I not see a pattern

in the residuals

Regression test of the slope

**Is it normal?**

No, and my sample

size is small

You are stuck

Go ask a statistician for

a Bayesian model

Yes it says it

is normal

No, but n>30 for

every group

Are the standard

deviations equal?

No, it does

not say so

You are stuck.

Go ask a statistician for

Levene's Test or

ANCOVA

Yes, it says so

MSE

MSG

DFE

SSE

DFG

SSG

MSG/MSE

SSE/DFE

SSG/DFG

N-1

N-k

k-1

SST

**ANOVA**

ANalysis Of VAriance

SSR/σ2

SSR

N-1

N-2

1

Using ANOVA

Using ANOVA

SSE