Question

The P-value for a chi-square test is always one-tailed. This is true because of all of the following reasons, EXCEPT:

Group of answer choices

Observed data that is either higher or lower than the null hypothesis predicts will result in a positive chi-square value.

Only a *large positive* value of chi-square provides
stronger evidence to conclude H_{A}.

A chi-square distribution is skewed.

The chi-square statistic is always positive, unlike a *z*
or *t* statistic which can be ether positive or
negative.

_______________________

For a two-way classification table, we define:

n = total # of observations

r = # of rows in the table

c= # of columns in the table

For the *Chi-Square Test of Independence*, the degrees of
freedom (df) is:

Group of answer choices

r x c - 1

n

n-1

(r-1)x(c-1)

_______________________________

What are the correct hypotheses for the *Chi-Square Test of
Independence*,?

Group of answer choices

H_{0}: A change in one variable does not cause a change
in the other variable.

H_{A}: A change in one variable does cause a change in
the other variable.

H_{0}: The variables of interest are dependent.

H_{A}: The variables of interest are independent.

H_{0}: The variables of interest are related to each
other.

H_{A}: The variables of interest are not related.

H_{0}: The variables of interest are independent.

H_{A}: The variables of interest are dependent.

_______________

Suppose you run a Chi-Squared Test of Independence on a 3-by-4 table and obtain a chi-squared value of 13.21. According to Table F, the P-value is:

Group of answer choices

between 0.025 and 0.05

between 0.05 and 0.10

between 0.02 and 0.025

between 0.01 and 0.02

Answer #1

The P-value for a chi-square test is always one-tailed. This is true because of all of the following reasons except A chi-square distribution is skewed. Since skewness does not affect the direction if test (like t distribution is also skwed bit we can test in both direction)

2) The degree of freedom for chi-square test is (r-1)*(c-1)., where r and c are the number of eows and coloumn respectively.

3) to Chi-square test, the null and alternative hypothesis are as

H0: The variables of interest are independent.

HA: The variables of interest are dependent. (since Chi-square test can be apply to test the dependency of two random variables)

4) For Chisquare value 13.21 with degree of freedom (3-1)*(4-1) = 6, P_value = P[Chisq>13.21] = 0.03982

therefore, P-value is between 0.025 and 0.05.

Explain why is the p-value for chi-square tests is
always “one sided”
describe how to obtain a p-value for a
chi-squared test for goodness of fit
and describe how to obtain a p-value for a t-test and a
critical t-score (t★) for a confidence interval
Describe how to obtain a p-value for a chi-squared test
for independence.

In a Chi-Square Independence test the test statistic is 1.88 and
the critical value is 3.84. Which of the following can we
conclude?
Reject H0 and conclude that the variables are related
Reject HO and conclude that the variables are not related
Not reject H0 and conclude that the variables are related
Not reject H0 and conclude that the variables are not
related

Given the following contingency table, conduct a test for
independence at the 1% significance level. (You may find it
useful to reference the appropriate table: chi-square table or F
table)
Variable A
Variable B
1
2
1
38
43
2
32
62
a. Choose the null and alternative hypotheses.
H0: The two variables are independent.;
HA: The two variables are dependent.
H0: The two variables are dependent.;
HA: The two variables are independent.
b. Calculate the value of the test...

Given the following contingency table, conduct a test for
independence at the 10% significance level. (You may find it useful
to reference the appropriate table: chi-square table or F table)
Variable A Variable B 1 2 1 32 39 2 35 51 a. Choose the null and
alternative hypotheses. H0: The two variables are independent.; HA:
The two variables are dependent. H0: The two variables are
dependent.; HA: The two variables are independent. b. Calculate the
value of the test...

1) One difference between a chi-square test and an analysis of
variance is that in a chi-square test all variables are?
2) The formula for the chi-square statistic is
Group of answer choices
O/[Σ(O–E)2].
[Σ(O–E)2]/F.
Σ[(O–E)2/E].
E/[Σ(O–E)2].

If the p-value for a Chi-square test for independence is 0.004,
the corresponding one-sided (or directional) p-value is always half
of 0.004.
True or False

Explain why is the p-value for chi-square tests is
always “one sided”, describe how to obtain a
p-value for a chi-squared test for goodness of fit, and
describe how to obtain a p-value for a t-test and
a critical t-score (t★) for a confidence interval.

A chi-square test for independence is being used to evaluate the
relationship between two variables. If the test has df = 3, what
can you conclude about the two variables?
One variable consists of 2 categories and the other consists of
3 categories
One variable consists of 2 categories and the other consists of
4 categories
Both variables consists of 2 categories
Both variables consists of 3 categories

How is the chi-square independence test similar to the
goodness-of-fit test? How is it different?
What is the difference between McMemar’s Test and the
Chi-squared test for 2 by 2 table.
Question 2
A clinic administers two drugs to two groups of randomly
assigned patients to cure the same disease: 70 patients received
Drug 1 and 80 patients received Drug 2. The following table gives
the information about the number of patients cured and the once not
cured by each...

The Chi square test is used to (select all that apply):
Test for association between two categorical variables
Compare a categorical variable across two independent
samples
Test a single categorical variable for goodness-of-fit to a
proposed distribution
None of the above

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