stats 7

Question 1

first step of hypothesis testing

Answer 1

State the null hypothesis

Question 2

second step of hypothesis testing

Answer 2

Set a critical value

Question 3

third step of hypothesis testing

Answer 3

Calculate a test statistic.

Question 4

fourth step of hypothesis testing

Answer 4

Compare the test statistic to the critical value

Question 5

fifth step of hypothesis testing

Answer 5

Find the p-value

Question 6

sixth step of hypothesis testing

Answer 6

Compare the p-value of your data to the critical value’s significance
level.

Question 7

Choose a difference in means test: 1. when testing 2 variables, if

Answer 7

the independent variable is categorical and the dependent variable is
numeric,
3. the numeric dependent variable is normally distributed, and
4. you are interested in the difference in the average values of the dependent variable across the categories of independent variable

Question 8

significance level, alpha (a)

Answer 8

the probability of rejecting the null hypothesis when its actually true, representing the threshold for statistical significance

Question 9

difference in means testing relies on the student’s

Answer 9

t-distribution

Question 10

The student’s t distribution is

Answer 10

the distribution of the values that the differences in sample means can take.

Question 11

The Student’s t distribution is generally

Answer 11

bell-shaped, like the normal
distribution

Question 12

However, when the sample size is small (less than 30 observations), the Student’s t-distribution shows

Answer 12

increased variability (i.e., is
flatter) than the normal distribution.

Question 13

Independent sample t-test

Answer 13

a statistical test that compares the means of two independent groups to see if there is a significant difference

Question 14

Paired Samples t-test (Dependent t-test)

Answer 14

a statistical test that compares the means of two related groups or matched pairs.

Question 15

One-Sample t-test

Answer 15

a statistical test that compares the mean of a
single sample to a known value (often the population mean)

Question 16

Each of these tests can be

Answer 16

one- or two-tailed

Question 17

One-tailed t-test

Answer 17

a statistical test used to determine if there is a significant difference in the means of two groups, with a specific directional hypothesis.

Question 18

The one-tailed t-test only looks at

Answer 18

one end (tail) of the distribution

Question 19

Two-tailed t-test

Answer 19

a statistical test used to determine if there is a
significant difference in the means of two groups, without specifying a direction

Question 20

The two-tailed t-test looks at

Answer 20

both ends (tails) of the
distribution

Question 21

Normality

Answer 21

he data in each group should be approximately
normally distributed
-* This assumption is particularly important when sample sizes are small
(typically n < 30).
* For larger sample sizes, the t-test is robust to violations of normality
due to the Central Limit Theorem

Question 22

Homogeneity of Variances

Answer 22

the variances of the two groups should be equal (or approximately equal
* Homogeneity can be tested using Levene’s test or Bartlett’s test.
* If the variances are significantly different, you may need to use a
Welch’s t-test, which does not assume equal variances.

Question 23

test of significance

Answer 23

asking whether the difference between populations

Question 24

difference between means

Answer 24

if we compare an infinite number of pairs of reasonably large samples from this population, we could form a frequency distribution of the differences between pairs of sample means

Question 25

a difference between means is another

Answer 25

statistic, its descriptive of two samples, rather than one

Question 26

we need to identify the - of a difference

Answer 26

direction

Question 27

the centre point of the distribution represents the

Answer 27

frequency of pairs of samples with zero difference between their means

Question 28

sampling distribution of the differences between means

Answer 28

differences between two means of a huge number of pairs of random samples drawn from the same population.

Question 29

standard error of the differences between means

Answer 29

the dispersion in the distribution of differences between sample means can be measured in standard deviation units

Question 30

in significance testing there are two opposite risks

Answer 30

type 1 error type 2 error

Question 31

type 1 error

Answer 31

-someone may accept a difference as significant when it is not

Question 32

we guard against a type 1 error by

Answer 32

demanding a more stringent level of significance (ex 1% rather than 5%)

Question 33

type 2 error

Answer 33

-if we ask for a bigger difference between sample means before we'll accept that there is a real difference between the populations, then the more likely it is that we'll fail to recognize a difference as being real

Question 34

the emphasis is on avoiding type ---- errors

Answer 34

1

Question 35

the greater the difference in standard deviation between 2 samples, the ---

Answer 35

less accurately can we establish the significance of the difference between their means.

Question 36

parametric

Answer 36

it is a fact that most of the classical statistical techniques assume that samples are drawn from normally distributed populations and allow us to estimate the parameters of such populations.

Question 37

the idea of normal distribution is inappropriate to

Answer 37

category-data

Question 38

non parametric tests require differences to be much

Answer 38

bigger if they are to be accepted as significant

Question 39

when both variables are continuous-

Answer 39

we can visually detect covariation

Question 40

researchers should state if using a 1 or 2 tailed test -

Answer 40

before collecting the data

Question 41

what does 1% imply

Answer 41

we want a difference between means so large that the probability of its occurring by chance from the theoretical 'no difference' population mentioned above would be 1% or less

Question 42

critical region

Answer 42

where the alternative hypothesis will seem more acceptable to us than the null hypothesis

Question 43

z test

Answer 43

use standard deviation as a unit (z unit) for measuring the point where the critical region begins and relate it to the proportions of the normal curve

Question 44

large samples are only accurate with

Answer 44

z-tests

Question 45

with samples of less than 30, - tests are used

Answer 45

t-tests

Question 46

a test where several samples can be compared at once

Answer 46

f test- analysis of variance