module 8 Flashcards
single sample t test
- statistical test that compares a sample mean of a numerical variable to a reference value.
what are single sample t tests used for
- evaluating if a sample mean is different than another samples mean/reference value
what are the steps in conducting a single sample t test
- define the null and alt hypothesis
- establish the null distribution
- conduct the statistical test
- draw scientific conclusions
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
c)
- sample mean (m) can change but the reference value (μ) is fixed
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
d)
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
b) and c)
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
a)
what two values are compared in a statistical test for single sample t tests
type I error rate (alpha) against the p value
t or f: If the p-value is less that the Type I error rate (p<⍺), then we reject the null hypothesis.
true
If the p-value is greater than or equal to the Type I error rate (p≥⍺), then we _______ the null hypothesis
fail to reject
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
b)
paired sample t test
- statistical test that compares the difference between paired measurements of a numerical variable to a reference value
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
two, sampling unit
when are two data considered paired
when the two measurements come from the same sampling unit
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
b)
paired sample t tests use the ______ between the measurements for inference rather than the individual measurements
difference
what is the difference in steps for conducting single sample and paired sample t tests?
there is no difference, it uses the same steps
to simplify paired sample t tests, we refer to the difference between the measurements as ___ and the reference value as ____
d, μ
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 ___________
reference value
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
c)
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
c) and d)
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
a)
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
d)
Are married couples less happy than unmarried couples? and Do dogs sleep more than cats?are examples of ____ sample t-test
two
two sample t tests see if the mean of a sample from one group is different from _________
the mean of a sample from another group
t or f: in two sample t test, sampling units in one group are dependent from sampling units of another group
false they are independent
what are two sample t tests also known as
independent sample t tests
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
b)
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
a) and c)
degrees of freedom for a two sample t test
- df=n1+n1-2
- n= number of sampling units
