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Volunteers at a teen hotline have been assigned based on the assumption that 40%

ID: 3361637 • Letter: V

Question

Volunteers at a teen hotline have been assigned based on the assumption that 40% of all calls are drug related, 25% are sex related, 25% are stress related, and 10% concern educational issues. For this investigation each call is classified into one category based on the primary issue raised by the caller. To test the hypothesis, the following data are collected from 120 randomly selected calls placed to the teen hotline. Based on the data, is the assumption regarding distribution of topic issues appropriate? Use alpha=.05.  

1) the appropriate null and alternative hypotheses; 2) the appropriate test (CHI SQUARE OR ANOVA); 3) the decision rule; 4) the calculation of the test statistic; and 5) your conclusion including a comparison to alpha or the critical value. You MUST show your work to receive full credit. Partial credit is available.

DRUGS SEX STRESS EDUCATION # OF CALLS 50 37 25 8

Explanation / Answer

Result:

Volunteers at a teen hotline have been assigned based on the assumption that 40% of all calls are drug related, 25% are sex related, 25% are stress related, and 10% concern educational issues. For this investigation each call is classified into one category based on the primary issue raised by the caller. To test the hypothesis, the following data are collected from 120 randomly selected calls placed to the teen hotline. Based on the data, is the assumption regarding distribution of topic issues appropriate? Use alpha=.05.  

1) the appropriate null and alternative hypotheses;

Null hypothesis: distribution of primary issue raised are based on given distribution.  

Alternative hypothesis: distribution of primary issue raised are based on different distribution

2) the appropriate test :CHI SQUARE test

3) the decision rule;

df=3

Critical chi square value : 7.815

Reject Ho if calculated value > 7.815

4) the calculation of the test statistic; and

Goodness of Fit Test

observed

expected

O - E

(O - E)² / E

50

40*120/100=   48.000

2.000

0.083

37

25*120/100=   30.000

7.000

1.633

25

25*120/100= 30.000

-5.000

0.833

8

10*120/100=12.000

-4.000

1.333

Total

120

120.000

3.883

5) your conclusion including a comparison to alpha or the critical value. You MUST show your work to receive full credit. Partial credit is available.

Calculated chi square =3.883 < critical value 7.815.

Ho is not rejected.

We conclude that distribution of primary issue raised are based on the given distribution.

Goodness of Fit Test

observed

expected

O - E

(O - E)² / E

50

40*120/100=   48.000

2.000

0.083

37

25*120/100=   30.000

7.000

1.633

25

25*120/100= 30.000

-5.000

0.833

8

10*120/100=12.000

-4.000

1.333

Total

120

120.000

3.883