# 11.14: Chapter Solution (Practice + Homework)

- Page ID
- 6140

**1**.

mean = 25 and standard deviation = 7.0711

**3**.

when the number of degrees of freedom is greater than 90

**5**.

\(df = 2\)

**6**.

a test of a single variance

**8**.

a left-tailed test

**10**.

\(H_0: \sigma^2 = 0.812\);

\(H_a: \sigma^2 > 0.812\).

**12**.

a test of a single variance

**16**.

a goodness-of-fit test

**18**.

3

**20**.

2.04

**21**.

We decline to reject the null hypothesis. There is not enough evidence to suggest that the observed test scores are significantly different from the expected test scores.

**23**.

\(H_0\): the distribution of AIDS cases follows the ethnicities of the general population of Santa Clara County.

**25**.

right-tailed

**27**.

2016.136

**28**.

**30**.a test of independence

a test of independence

**34**.8

**36**.6.6

**39**.Smoking level per day African American Native Hawaiian Latino Japanese Americans White Totals 1-10 9,886 2,745 12,831 8,378 7,650 41,490 11-20 6,514 3,062 4,932 10,680 9,877 35,065 21-30 1,671 1,419 1,406 4,715 6,062 15,273 31+ 759 788 800 2,305 3,970 8,622 Totals 18,830 8,014 19,969 26,078 27,559 10,0450 Table \(\PageIndex{54}\) **41**.Smoking level per day African American Native Hawaiian Latino Japanese Americans White 1-10 7777.57 3310.11 8248.02 10771.29 11383.01 11-20 6573.16 2797.52 6970.76 9103.29 9620.27 21-30 2863.02 1218.49 3036.20 3965.05 4190.23 31+ 1616.25 687.87 1714.01 2238.37 2365.49 Table \(\PageIndex{55}\) **43**.10,301.8

**44**.right

**46**.**48**.test for homogeneity

test for homogeneity

**52**.All values in the table must be greater than or equal to five.

**54**.3

**57**.a goodness-of-fit test

**59**.a test for independence

**61**.Answers will vary. Sample answer: Tests of independence and tests for homogeneity both calculate the test statistic the same way \(\sum_{(i j)} \frac{(O-E)^{2}}{E}\). In addition, all values must be greater than or equal to five.

**63**.true

**65**.false

**67**.225

**69**.\(H_0: \sigma^2 \leq 150\)

**71**.36

**72**.Check student’s solution.

**74**.The claim is that the variance is no more than 150 minutes.

**76**.a Student's \(t\)- or normal distribution

**78**.