HW10_skeleton

10.1

9.

Right-tailed, Mue

10.

Left-tailed, Sigma

11.

Two-tailed, Sigma

12.

Right-tailed, p

13.

Left-tailed, Mue

14.

Two-tailed, Sigma

15.

Ho: p = 0.399

H1: p > 0.399

17.

Ho: M = $245,700

H1: M < $243,700

19.

Ho: Sigma = 0.7 psi

H1: Sigma < 0.7 psi

21.

Ho: M = $48.79

H1: M (does not equal) $48.79

10.2

7.

1. test statistic: 2.31

2. p hat = 75/200= 0.375

3. This is a right tailed test, so the critical value is 0.05. 1.645 is greater that 0.5 we reject the null hypothesis.

• p-value = P(z>2.31) = 0.0104 Sice the p value is less than the level of significance, we again reject the null hypothesis.

9.

1. test statistic:z= -0.74 level of significance: = -1.28

2. sample proportion is p(hat)= 78/150 = 0.52

3. Since the p value: P(z < -0.74) = 0.2296, and that number is greater than the level of significance, the null hypothesis is not rejected.

11.

1. Test statistic: z= -1.49

2. p-value = 0.1362

3. Since p-value is greater than the level of significance, don’t reject the null hypothesis.

13.

p-value = 0.2743, therefore the null hypothesis that is true would be between 27% and 28% of 100%.

15.

1. 320/678=.472

2. Ho: P = 0.5 H1: P < 0.5

3. Random, n < or equal to 0.5N, np(1-p) is > or equal to 10

4. Skip

5. Test statistic: z = -1.45 P value = P(z<-1.45) = 0.0745

6. Looking at p-value we see that the null hypothesis is true.

7. 0.0735>0.05, therefore, we do not reject the null hypothesis. (p value is greater than alpha)

17.

1. Ho: p=0.019 H1: p >0.19 Level of significance: .01

sample proportion: .022

z = 0.65 –> when plotting, it lands in the middle, so we accept the null hypothesis

critical value = 2.32

p-value: P(z>0.65) = 0.2578 –> look at this for p-value hypothesis: 0.2578 is greater than .01 (level of significance), therefore we wont reject it.

2. .65<2.33 - so we don’t reject null hypothesis

19.

1. Ho: p = .36 H1: p > .36 critical value: .05

51/105 = P(hat) = .49

Test statistic: z = p (hat) - p / (square root of) p (1-p)/n (.49-.36)/(square root) (.36(.64)/105) = 2.77

cricitcal value = 1.645

P-value: p (z > 2.77) = 0.0028 --> find answer in table 

2. 2.77 > 1.645, therefore reject the null hypothesis.