module 8

Question 1

single sample t test

Answer 1

• statistical test that compares a sample mean of a numerical variable to a reference value.

Question 2

what are single sample t tests used for

Answer 2

• evaluating if a sample mean is different than another samples mean/reference value

Question 3

what are the steps in conducting a single sample t test

Answer 3

• define the null and alt hypothesis
• establish the null distribution
• conduct the statistical test
• draw scientific conclusions

Question 4

to simplyfy in null and alt hypotheses for single sample t tests, ___ refers to the sample mean and ___ refers to the reference value

a) μ, r
b) m, r
c) m, μ
d) m, Σ

Answer 4

c)
- sample mean (m) can change but the reference value (μ) is fixed

Question 5

null and alt hypotheses for single sample t-test with no directionality

a) Ho: m≤μ and Ha: m>μ
b) Ho: m≠μ and Ha: m=μ
c) Ho: m<μ and Ha: m≤μ
d) Ho: m=μ and Ha: m≠μ

Answer 5

d)

Question 6

null and alt hypotheses for single sample t-test with directionality

a) Ho: m≤μ and Ha: m<μ
b) Ho: m≥μ and Ha: m<μ
c) Ho: m≤μ and Ha: m>μ
d) Ho: m<μ and Ha: m≤μ

Answer 6

b) and c)

Question 7

null distribution for single sample and paired sample t test is also known as a:

a) t-distribution
b) x-distribution
c) t-test distribution
d) it has no other name

Answer 7

a)

Question 8

what two values are compared in a statistical test for single sample t tests

Answer 8

type I error rate (alpha) against the p value

Question 9

t or f: If the p-value is less that the Type I error rate (p<⍺), then we reject the null hypothesis.

Answer 9

true

Question 10

If the p-value is greater than or equal to the Type I error rate (p≥⍺), then we _______ the null hypothesis

Answer 10

fail to reject

Question 11

reporting of a sample mean should include all but:

a) degrees of freedom
b) null and alternative hypotheses
c) observed t-score (two decimals)
d) p-value (three decimals)
e) sample mean and standard deviation

Answer 11

b)

Question 12

paired sample t test

Answer 12

• statistical test that compares the difference between paired measurements of a numerical variable to a reference value

Question 13

paired sample t tests look at how sampling units change across a factor by taking _____ measurements from each ______, taken from locations or points in time

Answer 13

two, sampling unit

Question 14

when are two data considered paired

Answer 14

when the two measurements come from the same sampling unit

Question 15

paired sample t test measures if a factor ____ in two measurements

a) increases or decreases the change
b) causes a change
c) is stronger or weaker

Answer 15

b)

Question 16

paired sample t tests use the ______ between the measurements for inference rather than the individual measurements

Answer 16

difference

Question 16

what is the difference in steps for conducting single sample and paired sample t tests?

Answer 16

there is no difference, it uses the same steps

Question 17

to simplify paired sample t tests, we refer to the difference between the measurements as ___ and the reference value as ____

Answer 17

d, μ

Question 18

The null and alternative distributions for a paired-sample t-test are statements about how the difference between the paired measurements is related to the ___________

Answer 18

reference value

Question 19

in a paired same t test, the null and alt hypotheses if there is directionality are:

a) Ha: d<μ and Ha: d<μ
b) Ha: d≠μ and Ha: d=μ
c) Ha: d=μ and Ha: d≠μ
d) Ha: d<μ and Ha: d≠μ

Answer 19

c)

Question 20

in a paired same t test, the null and alt hypotheses if there is directionality are:

a) Ha: d<μ and Ha: d<μ
b) Ha: d≠μ and Ha: d=μ
c) Ho: d≤μ and Ha: d>μ
d) Ha: d≥μ and Ha: d<μ

Answer 20

c) and d)

Question 21

degrees of freedom for a paired sample t test is:

a) df= number of differences - 1
b) df= Ho - 1
c) df= median - 1
d) df= p-value - 1

Answer 21

a)

Question 22

The reporting of a paired-sample t-test should include all but:

a) the mean difference between the paired measurements
b) the standard deviation of the differences
c) the observed t-score (two decimal places)
d) t-test outcome
e) the p-value (three decimal places)
f) degrees of freedom

Answer 22

d)

Question 23

Are married couples less happy than unmarried couples? and Do dogs sleep more than cats?are examples of ____ sample t-test

Answer 23

two

Question 24

two sample t tests see if the mean of a sample from one group is different from _________

Answer 24

the mean of a sample from another group

Question 25

t or f: in two sample t test, sampling units in one group are dependent from sampling units of another group

Answer 25

false they are independent

Question 26

what are two sample t tests also known as

Answer 26

independent sample t tests

Question 27

in a two sample t test, the null and alt hypotheses if there is no directionality are:

a) Ho: m1<m2 and Ha: m1≠m2
b) Ho: m1=m2 and Ha: m1≠m2
c) Ho: m1≠m2 and Ha: m1=m2
d) Ho: m1>m2 and Ha: m1<m2

Answer 27

b)

Question 28

in a two sample t test, the null and alt hypotheses if there is no directionality are:

a) Ho: m1≥m2 and Ha: m1<m2
b) Ho: m1=m2 and Ha: m1≠m2
c) Ho: m1≤m2 and Ha: m1>m2
d) Ho: m1>m2 and Ha: m1<m2

Answer 28

a) and c)

Question 29

degrees of freedom for a two sample t test

Answer 29

• df=n1+n1-2
• n= number of sampling units