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1.For which confidence interval for the difference in the means 12, would you re

ID: 3129646 • Letter: 1

Question

1.For which confidence interval for the difference in the means 12,

would you reject the null hypothesis?

A.

(minus1.968,1.561)

B.

(minus2.001,minus1.873)

C.

(minus1.673,1.892)

D.

(minus2.209,0.209)

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2.Find the standardized test statistic t for a sample with n=20, x=7.8 s=2.0, x=0.05 if Ha: < 8.2.

Round your answer to two decimal places.

A.

minus1.23

B.

minus0.89

C.

minus0.87

D.

minus1.27

3. Find the critical value for a left-tailed test with =0.05 and n=48.

A.

minus1.645

B.

minus2.575

C.

minus2.33

D.

minus1.96

4. A researcher claims that 55% of voters favor gun control. Determine whether the hypothesis test for this claim is left-tailed, right-tailed, or two-tailed.

A.

two-tailed

B.

right-tailed

C.

left-tailed

5. Find the critical value and rejection region for the type of t-test with level of significance and sample size n. Right-tailed test, =0.01, n=32

A.

t0=2.453; t>2.453

B.

t0=1.309; t>1.309

C.

t0=2.449; t>2.449

D.t0=2.453; t<2.453

6. Find the standardized test statistic to test the claim that 1>2. Two samples are randomly selected from each population. The sample statistics are given below.

n1=100, n2=125, x1=650, x2=635, 1=45, 2=25

A.

2.99

B.

0.91

C.

1.86

D.

2.81

7. Given H0: p0.45, for which confidence interval should you reject H0?

A.

(0.32,0.40)

B.

(0.40,0.50)

C.

(0.42,0.47)

9. Use the given information to find the P-value. Also, use a 0.05 significance level and state the conclusion about the null hypothesis (reject the null hypothesis or fail to reject the null hypothesis).

The test statistic in a left-tailed test is z=1.83.

A.

0.0336; reject the null hypothesis

B.

0.0672; reject the null hypothesis

C.

0.0672; fail to reject the null hypothesis

D.

0.9664; fail to reject the null hypothesis

24. Construct a 90% confidence interval for 1-2. Two samples are randomly selected from normal populations. The sample statistics are given below. Assume that 2/1=2/2.

n1=10, n2=12, x1=25, x2=23, s1=1.5, s2=1.9

A.

(1.335,3.012)

B.

(1.413,3.124)

C.

(0.721,3.279)

D.

(1.554,3.651)

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Explanation / Answer

1.

We reject Ho when the confidence interval is entirely positive or entirely negative.

hence,

OPTION B: (2.001, 1.873) [ANSWER]

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2.

Formulating the null and alternative hypotheses,              
              
Ho:   u   >=   8.2  
Ha:    u   <   8.2  
              
As we can see, this is a    left   tailed test.      
              
Getting the test statistic, as              
              
X = sample mean =    7.8          
uo = hypothesized mean =    8.2          
n = sample size =    20          
s = standard deviation =    2          
              
Thus, t = (X - uo) * sqrt(n) / s =    -0.89 [ANSWER, B]          

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