King Abdul-Aziz University Assignment (6) Second Semester (1435-1436H) Stat 271 Faculty of Science
Department of Statistics
1- A nonparametric method to compare two populations, when the samples are independent and the data are either ordinal or interval, and where the normality requirement necessary to perform the parametric test is not satisfied, is the:
A ) sign test
B) Wilcoxon signed rank test C ) equal-variance t-test of 1 2
D) Wilcoxon rank sum test or Mann-Whitney test
2- In order not to violate the requirements necessary to use the chi-square distribution, each expected frequency in a goodness of fit-test must be
A) at most 5 B) at least 5 C ) at least 10 D ) at most 10
3- Three new colors have been proposed for the Jeep Grand Cherokee vehicle. They are silvered-blue, almond, and willow green. The null hypothesis for a goodness-of-fit test would be
A ) willow green is preferred over the other colors.
B ) that there is no preference between the colors.
C ) any one color is preferred over the other colors.
D) impossible to determine
A personnel manager is concerned about absenteeism. She decides to sample the records to determine if absenteeism is distributed evenly throughout the six-day workweek. The null
hypothesis to be tested is: Absenteeism is distributed evenly throughout the week. The 0.01 level is to be used. The sample results are:
4- What kind of frequencies are the numbers 12, 9, 11, 10, and 9 called?
A) Acceptance B ) Critical value C ) Expected D) Observed
5 - How many degrees of freedom are there?
A ) 0 B ) 3 C) 4 D) 5
6 - What is the expected frequency?
A ) 9 B ) 10 C ) 11 D ) 12
7 - What is the calculated value of chi-square?
A ) 1.0 B ) 0.5 C ) 0.8 D ) 8.0
8 - The ...test is used to test means when samples are dependent and the normality assumption is violated .
A) Wilcoxon signed - rank B ) Wilcoxon rank sum C ) Z- test
D ) Kruskal - Wallis
THE NEXT THREE QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
Two groups of teas drink, one group male and the other female, were asked at what age they first drank tea . The data are shown here. Using the Wilcoxon rank sum test at =0.05 , is there a difference in the ages of the females and males?
Male 6
12 14
16 17
17 13
12 10
11
Female 8
9 9
12 14
15 12
16 17
19
9- The test statistics value is:
A) 2.58 B) 1.96 C ) -0.04 D ) 0.04
10 - The decision is:
A ) There is not enough evidence to reject the null hypotheses B ) There is not enough evidence to reject the alternate hypotheses C ) There is enough evidence to reject the null hypotheses
D) The information is not enough
11 - Suppose we run the regression Y 01X12X23X34X4 using a sample of 30 observations. What is the alternative hypothesis for the F- test of overall significance?
A ) H1:atleast one j 0 B ) H1:12 3x3 4 0 C ) H1:0 1 2 3x3 4 0 D ) H1:12 3x3 4 0
12 -In a multiple regression analysis involving 6 independent variables, the total variation in y is 900 and SSR = 600.
What is the value of SSE?
A) 300 B ) 1.50 C ) 0.67
D ) None of the above
THE NEXT 3 QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
An art collector is studying the relationship between the selling price of a painting and two independent variables: the number of bidders at the particular auction and the age of the painting (in years). A sample of 25 paintings revealed the following.
R2 = 0.648 n = 25 k = 2
ANOVA table
Source SS df MS F p-value
Regression 1,995,489.1234 2 997,744.5617 20.23 1.03E-05 Residual 1,084,910.8766 22 49,314.1308
Total 3,080,400.0000 24
Regression output
variables coefficients std. error t (df=22) p-value Intercept 3,080.0530 343.8849 8.957 8.62E-
09 Bidders -54.1885 12.2815 -4.412 .0002
Age 16.2891 3.7839 4.305 .0003
13 - The linear multiple regression line is given by:
A ) y = -54.1885+3,080.0530 x1+16.2891 x2 B ) y = 16.2891-54.1885 x + 3,080.0530x
14 - What can we conclude if the global test of regression does not reject the null hypothesis?
A) A strong relationship exists among the variables
B) No relationship exists between the dependent variable and any of the independent variables
C )The independent variables are good predictors D ) Good forecasts are possible
The best example of a null hypothesis for a global test of a multiple regression model is:
A) H0: B1 = B2 = B3 =B4 = 0 B ) H0: 1 2 3 4 C ) H0 : 1 2 3 4 D ) H0: B1 = 0
15- The best example of an alternate hypothesis for a global test of a multiple regression model is:
A) H1: B1 B2 B3 B4 B) H1: 1 2 3 4 C ) H1 : 1 2 3 4 D ) H1 : Not all the B's are 0
16 - A chi-square goodness -of -fit-test is to be performed. If the degrees of freedom are 8, and = 0.10, then the table chi-square value that defines the rejection region is A ) 13.362
B ) 15.507 C ) 17.535
D ) None of the above
17 - What is the critical value of chi-square with = 0.05?
A ) 11.070 B ) 12.592 C ) 13.388 D ) 15.033
