1)The standard error (SE) of X¯ is: 1 0

1)The standard error (SE) of X¯ is:

1. 1
2. 0.1111
3. 1.56
4. 0.98    

2. The critical value (CV) needed for 90% confidence interval estimation is:

1. 2.56
2. 1.67
3. 1.28
4. 1.64

3. The 90% confidence interval estimate of μ is

1. 67±1.66
2. 67±1.67
3. 67±1.87
4. 67±1.56

4) Suppose the Highway Safety Department claims that the average speed is 68 miles per hour. In light of the sample evidence and at the 10% level of significance, 

Select one:

1. We cannot reject Dell's claim
2. We can reject Dell's claim

5) If we increase the confidence level (1-α) from 0.90 to 0.95, the margin of error (ME) of the confidence interval estimate will

1. Increase
2. Decrease
3. Stays the same
4. be zero

6) The standard error (SE) of p¯ is

1. 0.352
2. 0.00352
3. 0.0352
4. 0.3352

7) The critical value (CV) needed for the 90% confidence interval estimation of p is

1. 1.56
2. -1.56
3. 2.56
4. 1.64

8) The 90% confidence interval estimate of p is

1. 0.7 ± 0.0512   
2. 0.7 ± 0.0419   
3. 0.7 ± 0.0119   
4. 0.7 ± 0.0578   

9) Suppose around the period the above sample was taken, H & R Block (a tax preparation company) claims that 72% of all individual tax returns are electronically filed. In light of the sample evidence and at the 10% level of significance,

1. We can reject the commentator's claim
2. We cannot reject the commentator's claim

10) Using the current sample proportion of p¯=0.7 (from the 169 individual tax returns) as a basis, what sample size (n) would be required to achieve a 10% margin of error?

1. 57
2. 56
3. 55
4. 54

11) The sampling distribution of X¯

1. is not normal because the sample size is too large
2. is not normal because the sample size is too small
3. is normal due to the Chebyshev's Theorem
4. is normal due to the Central Limit Theorem

12) The standard error (SE) of X¯ is

1. 5.3341
2. 5.5355
3. 5.3146
4. 5.5766

13) What is the probability that a random sample of 200 cellular customers will provide an average(X¯) that is within $10 of the population mean (µ)?

1. 0.9953
2. 0.8990
3. 0.9789
4. 0.9576

14) The probability in the PRECEDING question would ------ if we were to increase the sample size (n) from 200 to 246.

1. Decrease
2. Be Zero
3. Increase
4. Stays the same

15) Suppose we reduce the sample size (n) from 200 to 25. The sampling distribution of X¯ will be normal only if 

1. X is normally distributed
2. X has a left skewed distribution
3. X has a bi-modal distribution
4. X has a right skewed distribution

16) The sampling distribution of p¯ is normal because....

1. n*p >= 5 and n*(1-p) >= 5
2. n*p >= 5 and n*(1-p) <= 5
3. n*p >= 5 or n*(1-p) >= 5
4. n*p <= 5 or n*(1-p) >= 5

17) The standard error (SE) of   p¯ is

1. 0.0178
2. 0.0297
3. 0.0265
4. 0.0249

18) What is the probability that a random sample of 250 U.S. adults will provide a sample proportion (p¯) that is within 0.03 of the population proportion (p)?   (none of the option are the correct answer)

1. 0.7561
2. 0.8912
3. 0.4345
4. 0.7431

19) What is the probability that a random sample of 250 U.S. adults will provide a sample proportion (p¯) that is within 0.08 of the population proportion (p)?

)?  (none of the option are the correct answer)

1. 0.0711
2. 0.0751
3. 0.0890
4. 0.6573

20) Say, you took a random sample of 250 U.S. adults, and found out that the sample proportion (p¯) for this sample to be 0.32 (or 32%). In light of the result from the PRECEDING question, 

1. This is considered a very strange finding because a sample proportion of 32% should be extremely rare 
2. This is not considered a very strange finding because a sample proportion of 32% is quite likely

21) Specify the null and alternative hypotheses.

1. Ho: ? ≤ 25 ; Ha: ?  > 25
2. Ho: ? ≥ 25 ; Ha: ? < 25
3. Ho: ? < 25 ; Ha: ? ≥25
4. Ho: ? equal 25 ; Ha: ? not equals 25

22) The standard error (SE) of X¯ is

1. 0.781
2. 0.643
3. 0.512
4. 0.988

23) The test statistics value is

1. -7.432
2. 7.432
3. -6.222
4. 6.222

24) The p-value is 

1. 1.61
2. 2.12
3. 2.53
4. 2.45081E-10 (note: this means a very small number)

25) At α=0.10 and using the p-value

1. We reject Ho in favor of H(a)
2. We do not reject Ho

26) Specify the null and alternative hypotheses.

1. Ho: ? ≥ 520 ; Ha: ? < 520
2. Ho: ? < 520 ; Ha: ? ≥ 520
3. Ho: ? equal 520 ; Ha: ? not equals 520
4. Ho: ? ≤ 520 ; Ha: ?  > 520

27) The standard error (SE) of X¯ is

1. 21.878
2. 20.516
3. 20.997
4. 22.003

28) The test statistics value is 

1. 7.443
2. 6.712
3. 7.825
4. 5.617

29) The p-value is 

1. 4.527E-07
2. 4.420E-89
3. 4.147E-48
4. 4.127E-67

30) At α=0.01 and using the p-value

1. We reject Ho in favor of H(a)
2. We do not reject Ho

31) What is the null hypothesis H(0)?

1. ?1 – ?2 < 0
2. ?1 – ?2 ≤ 0
3. ?1 – ?2 ≥ 0
4. ?1 – ?2 = 0

32) What is the alternative hypothesis H(a)?

1. ?1 – ?2 < 0
2. ?1 – ?2 > 0
3. ?1 – ?2 not equals 0
4. ?1 – ?2 ≤ 0

33) What is the standard error of X¯1−X¯2?

1. 0.2387
2. 0.9006
3. 0.2507
4. 0.6724

34) What is the value of the test statistic?

1. 2.8711
2. 2.6599
3. 2.7926
4. 2.9082

35) What is the p-value?

1. 0.0261
2. 0.2612
3. 0.0026
4. 0.2812

36) At α=0.1 and using the p-value

1. We reject Ho in favor of H(a)
2. We do not reject Ho

37) Specify the null and alternative hypotheses using correct notations.

1. Ho: μd ≤ 0; Ha: μd > 0
2. Ho: μd < 0; Ha: μd > 0
3. Ho: μd ≥ 0; Ha: μd < 0
4. Ho: μd equals 0; Ha: μd not equals 0

38) What is the value of the test statistic?

1. 1.245
2. 2.761
3. 1.391
4. 4.223

39) At α=0.05 what is the critical value of the test?

1. 2.371
2. 2.015
3. 1.997
4. 3.114

40) At α=0.05 and using the correct critical value from the preceding question

1. We reject Ho in favor of H(a)
2. We do not reject Ho

41) What is the p-value?

1. 0.56
2. 0.23
3. 0.11
4. 0.37

42) Using the p-value approach, what is the correct statistical conclusion?

1. We reject Ho in favor of H(a)
2. We do not reject Ho