STAT 625
Summer 2014
Quiz # 4
1.) The null hypothesis usually represents the

a. 
theory the researcher would like to prove 

b. 
preconceived ideas of the researcher 

c. 
perceptions of the sample population 

d. 
status qu0 
2.) If we reject the null hypothesis, we conclude that:

a. 
there is enough statistical evidence to infer that the alternative hypothesis is true 

b. 
there is not enough statistical evidence to infer that the alternative hypothesis is true 

c. 
there is enough statistical evidence to infer that the null hypothesis is true 

d. 
the test is statistically insignificant at whatever level of significance the test was conducted at 
3.) A twotailed test is one where:

a. 
results in only one direction can lead to rejection of the null hypothesis 

b. 
negative sample means lead to rejection of the null hypothesis 

c. 
results in either of two directions can lead to rejection of the null hypothesis 

d. 
no results lead to the rejection of the null hypothesis 
4.) A low p–value provides evidence for accepting the null hypothesis and rejecting the alternative.
True
False
5.) If we perform a twotail independent samples ttest, our null hypothesis is about:

a. 
Equality of two sample means 

b. 
Difference of two sample means 

c. 
Equality of two population mean 

d. 
The mean of the population difference 
6.) The rejection region is the set of sample data that leads to the rejection of the alternative hypothesis.
True
False
7.) If a null hypothesis about a population mean is rejected at the 0.025 level of significance, then it must also be rejected at the 0.01 level.
True
False
8.) If the pvalue for the “equality of variances test” is greater than the alpha value set for that test, the appropriate test to choose if we were comparing the difference of two means is:

a. 
Equal variances independentsample ttest 

b. 
Unequal variances independentsample ttest 

c. 
Pairedsamples ttest 

d. 
None of the above 
9.) have sample data on five conferences and I would like to use it all for the test. I would test this hypothesis using:

a. 
Pairedsamples ttest with an equal sample of players from each conference 

b. 
Independentsamples ttest 

c. 
ANOVA 

d. 
Singlesample ttest on the difference in heights 
10.) In testing the null hypothesis that the population proportion is 0.75, at the 5% significance level, if the sample size is 10 and the sample proportion is 0.45, which one would be the appropriate conclusion? Note: z(0.975)=1.96


Reject the null hypothesis 


Fail to reject the null hypothesis 


Reject the alternative hypothesis 


Fail to reject the alternative hypothesis 
11.) A test for independence is applied to a contingency table with 4 rows and 4 columns. The degrees of freedom for this chisquare test must equal 9.
True
False
12.) The owner of a popular Internetbased auction site thinks that more than half of the people who sell items on her site are women. To test this hypothesis, the owner sampled 1000 customers who sold items on her site and she found that 53% of the customers sampled were women. The calculated zstatistic is 1.9 with pvalue of 0.028. What is the correct alternative hypothesis form for testing this hypothesis and what would be the owner’s conclusion at 5% significance level?

a. 
H(a):p < 0.5  She fails to conclude that women make up more than 50% of her customers 

b. 
H(a):p > 0.5  She can conclude that women make up more than 50% of her customers 

c. 
H(a):p>=0.5 She fails to conclude that women make up more than 50% of her customers 

d. 
H(a):p<=0.5  She can conclude that women make up more than 50% of her customers 
13.) Suppose we get the following significant results from a regression analysis where we used “productivity” measured on a 0100 scale as the dependent variable and “seniority” measured in years working at the company as the independent variable. Which choice is one of the correct interpretations where the intercept of the regression line is 96 and the slope of the regression line is 2.5:

a. 
For every additional year spent working at the company, the average productivity increases by 2.5 

b. 
For every additional year spent working at the company, the average productivity decreases by 2.5 

c. 
For every additional year spent working at the company, the average productivity increases by 96 

d. 
For every additional year spent working at the company, the average productivity decreases by 96 
14. ) A sport preference poll yielded the following data for men and women. In using the 5% significance level to test whether sport preference and gender are independent, what are the calculated figures of the test statistic and the pvalue?

Basketball 
Football 
Soccer 
Men 
20 
45 
30 
Women 
20 
15 
25 

a. 
tstatistic: 5.991 , pvalue: 0.049 

b. 
chisquare: 7.957 , pvalue: 0.0187 

c. 
tstatistic; 7.957 , pvalue: 0.05 

d. 
chisquare: 5.991 , pvalue: 0.05 
Subject  Mathematics 
Due By (Pacific Time)  08/04/2014 9:30pm 
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