Question

The type of household for the U.S. population and for a random sample of 411 households from a community in Montana are shown below.

Type of Household	Percent of U.S. Households	Observed Number of Households in the Community
Married with children	26%	104
Married, no children	29%	102
Single parent	9%	38
One person	25%	103
Other (e.g., roommates, siblings)	11%	64

Use a 5% level of significance to test the claim that the distribution of U.S. households fits the Dove Creek distribution.

(a) What is the level of significance?


State the null and alternate hypotheses.

H₀: The distributions are different.
H₁: The distributions are the same.

H₀: The distributions are different.
H₁: The distributions are different.    

H₀: The distributions are the same.
H₁: The distributions are different.

H₀: The distributions are the same.
H₁: The distributions are the same.

(b) Find the value of the chi-square statistic for the sample. (Round the expected frequencies to two decimal places. Round the test statistic to three decimal places.)


Are all the expected frequencies greater than 5?

Yes

No    

What sampling distribution will you use?

uniform

chi-square    

binomial Student's t

normal

What are the degrees of freedom?


(c) Find or estimate the P-value of the sample test statistic. (Round your answer to three decimal places.)


(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis that the population fits the specified distribution of categories?

Since the P-value > α, we fail to reject the null hypothesis.

Since the P-value > α, we reject the null hypothesis.    

Since the P-value ≤ α, we reject the null hypothesis.

Since the P-value ≤ α, we fail to reject the null hypothesis.

(e) Interpret your conclusion in the context of the application.

At the 5% level of significance, the evidence is sufficient to conclude that the community household distribution does not fit the general U.S. household distribution.

At the 5% level of significance, the evidence is insufficient to conclude that the community household distribution does not fit the general U.S. household distribution.

Answer 1

a)level of significance =0.05

H0: The distributions are the same.
H1: The distributions are different.

b)

applying chi square test:

		observed	Expected		Chi square
category	Probability(p)	Oi	Ei=total*p		R2i=(Oi-Ei)2/Ei
married with children	0.260	104.000	106.860		0.077
married no children	0.290	102.000	119.190		2.479
single parent	0.090	38.000	36.990		0.028
one person	0.250	103.000	102.750		0.001
other	0.110	64.000	45.210		7.809
total	1.000	411	411		10.393

chi-square statistic =10.393

Are all the expected frequencies greater than 5? --Yes

What sampling distribution will you use? --chi square

What are the degrees of freedom? - categories-1 =5-1=4

c)

p value =0.034

d)

Since the P-value ≤ α, we reject the null hypothesis.

e)

At the 5% level of significance, the evidence is sufficient to conclude that the community household distribution does not fit the general U.S. household distribution.