stats exam 3

If treatment has no effect, the sample mean ___

Should be close to the mu and lead you to FAIL to reject the null

SD can also be known as

s

If treatment has an effect, the sample mean ___

is not close to the mu

Variance

S2, measures average distance between each data point from the mean

X2

Chi square

when to use df=(R-1)(C-1)

Chi square

SM

Sample error of mean

What set of sample characteristics is most likely to produce a significant t statistic

Large sample size and a small sample variance

Higher chance of significance =

Large M, small variance

When N is small, how does the shape of the t distribution compare to the normal distribution

Flatter and more spread out

On the t value chart always use

0.5

When solving for single sample T test go in the order:

1. SM

2. t

3. df

It IS significant when

Obtained is larger than df score on table

You are most likely to get a significant (large) t-statistic with a ___ sample size and ___ sample variance

Large, small

This is used for categorical data (like gender and job title) to see if there is a relationship between variables

Chi square

compares means of continuous data

T tests

Checks if two variables (e.g., gender and favorite food) are related

Tests of independence

Compares observed values to a specific theory to see if the theory "fits" the data

goodness of fit

Paired Sample (Dependent) t-test

Used when you have two scores for the same person (e.g., a "before and after" study).

Single Sample t-test

Used to compare a sample mean to a known population mean

In a T test you have to calculate the

sample variance

For a T stat you don't need to I know the

population variance

On a T test when the obtained is larger

Reject null, and sufficient

On a T test when the critical is larger than the obtained

Maintain null, not sufficient

When it says “before and after”

Paired sample, use T test.

What are the steps for a paired sample T test?

1. Add everything up

2. get mean

3. square and add

4. solve SD

5. solve standard error of mean (SD/square root of N)

6. Mean/standard error

7. df (N - 1)

when it says “achieve an average accuracy of 65%” what is that

mu

when it says “finds an average accuracy of 70%”

M

When sample size goes up

sample variance goes down