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2/3 Examination: Sample Questions and Answers
Sample Questions for 2/3 Exam from Previous Years
Click on the "answer" term below for the answer and explanation.
 
Which test statistic --- (1) z-score, (2) t-score, (3) F ratio ---- would be most suitable for testing relationships between
these pairs of variables?
 
1.______ Difference in mens' and womens' attendance rates at religious services
 
2.______ Difference in the predicted mean Republican vote in 1998 by the Gallup poll with 900 interviews and the CBS poll with 1,200.
 
3.______ Literacy rates by countries and a classification of countries by region.

Answers for all three

 
4. The formula provides an unbiased estimate of the population:

1- standard deviation

2- standard error

3- sum of squares

4- variance

Answer

5. The standard error of the mean is
1- an unbiased estimate of the population mean
2- equal to the standard deviation of the sample data
3- the standard deviation of the sampling distribution of means
4- the descriptive statistic that measures dispersion

Answer

6. The standard error of the mean is equal to

Answer

7. Given a sample size of 100, mean of 36, population standard deviation of 5, and confidence level of .95, the confidence interval for the mean of the population is closest to

1- 31 to 41
2- 26 to 46
3- 35.5 to 36.5
4- 35 to 37
Answer

8. In practical terms, the amount of accuracy in predicting from national samples to the U.S. Population is least dependent on
1- the proportion that the sample is of the population
2- the absolute number of cases in the sample
3- the population variance for the attribute being estimated
4- the procedure used in drawing the sample

Answer

9. Which of the following terms does not belong with the other terms?
1- Type I error
2- alpha level
3- region of rejection
4- z-score
Answer
10. Which of the following statistical distributions is interpreted with reference to two different degrees of freedom?

1- F
2- t
3- skewed
4- normal
Answer

11. If one has a directional hypothesis, he or she especially wants to
1- make a one-tailed test
2- make a two-tailed test
3- guard against a Type I error
4- guard against a Type II error

Answer

12. The sampling distribution of the difference between two means for independent samples --
1- is unknown and therefore one cannot test differences between two means against a null hypothesis.
2- is not subject to the Central Limit Theorem.
3- has a standard error equal to the difference in the standard errors of the individual samples.
4- tends to become normal as the sample sizes increase.

Answer

13. In the analysis of variance model, the null hypothesis of no difference among the means for the subgroups will tend to be rejected as
1- the "between group" variance exceeds the "within group" variance.
2- the "within group" variance begins to exceed the "between group" variance.
3- the "within" and "between" group variance approach equality.
4- both the "between" and the "within" group variance approach total variance.

Answer

 
14. Which statement is true about data expressed in proportions?
1- You cannot treat proportions as interval data.
2- You cannot compute variance for a dichotomized variable expressed as proportions.
3- Proportions computed for a dichotomized variable are simply a type of mean.
4- Transforming percentage data into proportions is an example of a nonlinear transformation.

Answer

15. Another name for "between groups" sum of squares in the analysis of variance is
1- unexplained variation
2- deviations about the regression line
3- explained variation
4- error variance

Answer

16. An unbiased estimator of a population parameter is
1- a statistic whose mean value of its own sampling distribution is equal to the population parameter.
2- a statistic with a relatively small sampling error.
3- a statistic that predicts to the population with a known bias.
4- impossible to calculate if the population lacks a normal distribution.

Answer

17. Calculate the variance for this set of numbers: -5,-5,-5,5,5,5
Variance = _____

Answer

18. According to the table of areas under the normal curve, what positive and negative z-score value would be used to establish the region of rejection for a TWO-tailed test nearest to the .04 level of significance?
z-score = __________

Answer

 
Here is T-TEST output comparing Democrat and Republican Members of Congress, with the dependent variable being a scale of increasing"conservatism" in voting on social issues. Answer questions 19 and 20.
VARIABLE         NUMBER              STANDARD    STANDARD
                 OF CASES     MEAN   DEVIATION      ERROR 
    DEMOCRATS      248      30.5806     23.441      1.488 
    REPUBLICANS    180      65.7278     16.318      1.216 
                     
                Mean Difference = -35.1472
                     
                Levene's Test for Equality of Variances:F= 2.06  P= .000
   
   Variances    t-value     df    2-TailSig     
   
    Equal        -17.30     426      .000  
    Unequal      -18.28     425.31   .000
19.Which expression below was used to compute the degrees of freedom for Equal Variance estimate of the T-Test above?

1- (N - 1)
2- (k - 1)
3- (N - 2)
4- (N1 + N2 - 2)
Answer

 
20. Which statement about the above T-TEST output is true?
1- It shows that DEMOCRATS were actually more conservative on social issues than Republicans
2- It shows that REPUBLICANS showed much more variation in voting on conservative issues than DEMOCRATS.
3- The F-value is significant at the .05 level, indicating that the population variance are equal and that you are advised to use the Unequal variance estimate rather than the Equal estimate in checking the significance of t.
4- Regardless of which estimate you use, the T-TEST shows that both groups of Representatives do NOT differ significantly in voting on social issues, so the null hypothesis CANNOT be rejected.

Answer

 
Below is SPSSx output from MEANS for GNP PER CAPITA in the POLITY data analyzed by type of government. Answer questions 21, 22, 23, and 24 with reference to this output.
 
   DEPENDENT VARIABLE   GNPPCA80   GNP PER CAPITA IN US DOLLARS-1980
 INDEPENDENT VARIABLE   POLTYPE    TYPE OF POLITICAL SYSTEM
  
 VARIABLE      VALUE  LABEL                      MEAN    STD DEV    CASES 
  
 FOR ENTIRE POPULATION                      3633.0864  4267.0914       81   
 POLTYPE        1.00  PARLIAMENT/DEMOCRACY  6511.4815  4608.2098       27 
 POLTYPE        2.00  DEMOCRATIC & FEDERAL  9598.0000  5869.8825        5 
 POLTYPE        3.00  MULTIPARTY DEMOCRACY  1322.8571  1334.9746        7 
 POLTYPE        4.00  DEMOCRATIC FORM       2210.0000   113.1371        2 
 POLTYPE        5.00  MILITARY GOVERNMENT    895.8333   900.6408       12 
 POLTYPE        8.00  ONEPARTY COMMUNIST    3587.5000  2431.3180        8 
 POLTYPE        9.00  ONEPARTY SOCIALIST    2270.0000   494.9747        2  
 POLTYPE       10.00  ONEPARTY MARXIST       276.6667   140.1190        3 
 POLTYPE       11.00  ONEPARTY STATE         798.6667  1015.8168       15 
                     
                        SUM OF                MEAN
 SOURCE                 SQUARES    D.F.      SQUARE       F     SIG.
  
 BETWEEN GROUPS     690959683.13     8
 WITHIN GROUPS      765685845.26    72

21. Showing the math, compute the MEAN SQUARE for BETWEEN GROUPS to one decimal: _____________

Answer

 
22. Showing the math, compute the F ratio to one decimal: _____________

Answer

 
 
23. Which statement gives the most accurate assessment of that relationship?
1- The null hypothesis can be rejected at the .10 level.
2- The null hypothesis can be rejected at the .05 level.
3- The null hypothesis can be rejected at the .01 level.
4- The observed differences in GNP by government type can occur about 20 times out of 100 on the basis of chance alone.

Answer

24. Under the null hypothesis, the expected value of Pearson's r is
1- dependent on sample size
2- not used in two-tailed tests
3- unknown unless the t value is computed
4- zero

Answer

 
25. What condition exists when the variance of Y remains the same for different values of X?

1- homoscedasticity
2- unbiasedness
3- normality
4- linearity
Answer

 
26. This formula for testing the significance of r: , assumes that
1- the F table is used to determine level of significance.
2- that you have no degrees of freedom in computing the significance.
3- there is no difference between the observed and expected correlation.
4- the test is against the null hypothesis that the population correlation, r (rho), is equal to 0.

Answer

27. If data for 2 variables are transformed into z-scores and then correlated, [This topic was not covered.]
1- the product moment correlation will be equal to the beta coefficient in the associated regression equation.
2- the beta coefficient will be equal to the b-coefficient in the regression equation.
3- the intercept in the regression equation will be equal to 0.
4- all of the above are true.

Answer

 
28.Tested against the null hypothesis, a highly significant correlation merely indicates that
1- it is unlikely that there is no relationship between the variables in the universe.
2- knowledge of one variable will substantially improve prediction of the value of an observation on the other variable.
3- there is a strong relationship between the variables in the universe.
4- there is a strong relationship between the variables in the sample.

Answer

29. Which statistic is most appropriate for testing the significance of the difference among means for four independent samples?

1- t-test
2- beta coefficient
3- F ratio
4- b coefficient
Answer

 
30. The condition of heteroscedasticity is best shown in which diagram?

Answer