Department Of Economics and Political Sciences / Time Duration: Two hour
Date: 13 / 1 / 2008

Computer & Data Analysis Final Exam

Student’s Name: ...... Student ID #: ......

Question #1: (15 Points)

State True (T) or false(F)for the following statements

1- / ( ) / If X and Y are two independent variables then the covariance between them isnon zero
2- / ( ) / If we construct a 98% Confidence interval for . This means that 2% (1 in 50) of all possible intervals do not include .
3- / ( ) / Chi-Square Goodness of Fit Test assesses how well the sample data fits thepopulation proportion specified by the null hypothesis
4- / ( ) / In parametric tests when we want to compare two or more independent means to one another we will use analysis of variance command (ANOVA).
5- / ( ) / In Parametric tests to perform hypothesis tests concerning a population mean we will use independent samples TTest command.
6- / ( ) / Multiple regressions is used to estimate the influence of many independent variables on the dependent variable.
7- / ( ) / In nonparametric tests when we want to compare two independent means to one another we will use Mann-Whitney U test.
8- / ( ) / Adding any independent variable to a regression model will not influence
9- / ( ) / We can perform multiple Regression in the presence of quantitative variables only.
10- / ( ) / Chi-Square Test of independence is used for testing whether there is a statistical relationship between two qualitative or discrete variables.
11- / ( ) / Multicollinearity appears in the simple regression and multiple regression.
12- / ( ) / Levine's test is used as a test of homogeneity of the variances of two independent population.
13- / ( ) / In nonparametric tests the Wilcoxon signed Ranks test is used when we have repeated measures from one sample. And can be used with ordinal, interval or ratio data.
14- / ( ) / Time series data is drawn from a population at one point in time while cross sectional data involves repeated measurements of a s a sample a cross time.
15- / ( ) / A dummy variable is an artificial binary variable and it's impact to alter the intercept for the two different categories.

Question #2: (9 Points)

In the following study we develop a multiple regression model to estimate the total amount of sleep (sleep) required by a mammal species, based on the following variables Body weight, Brain weight, lifespan, Gestation. Results are given on the attached SPSS printout at Figure (2-1) Let , Depending on these results Answer the following Questions.

a) write the estimated regression equation.

b) Do the estimated coefficient have the expected sign? Explain.

c) Are the relationships between the total amount of sleep and each of the independent variables

statistically significant? Explain?

d) How well does the model fit the data? Explain.

e) Are the residuals normally distributed and homoskedastic? Explain?

f) What is your recommendation for the final regression model?

Question #3: (6 Points)

We have a study concerning the amount of time men and women spend watching TV.

Results are given on the attached SPSS printout at Figure (3-1). Let

Is there enough evidence to show that there is a statistically significant difference in the amount of time men and women spend watching TV?

a) State the null and alternative hypotheses in words.

b) What assumptions must be made in order for the test results to be valid? Do theyhold? Explain

by using the SPSS results.

c) Give the test statistic value.

d) Find the p-value and write a statement interpreting it in this problem.

e) State the decision in words.

Question # 4 : ( 20 points)

Write the difference between the following functions

1 - a) Ordinal Data :

b) Nominal Data :

2 - a) Time Series Data :

b) Cross Sectional Data :

3- a) Numeric Variable :

b) String Variable :

4 - a) Pearson Correlation Coefficient :

b) Spearman Correlation Coefficient :

5 - a) Explore :

b) Cross tabs :

6 - a) Paired Samples T Test :

b) Wilcox on Signed Ranks Test :

7- a) Box plot :

b) Histogram :

8- a) One-Way ANOVA :

b) Kruskal-Wallis H :

9 - a) Descriptive :

b) Frequency :

10- a) Independent- Samples T Test:

b) Mann-Whitney U :

Figure(2-1)

Figure(3-1)

The End

Good Luck

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