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1The right way to think about the sample mean is:    
aThe sample mean is a constant number.     
bThe sample mean is a different value in each random sample from the population mean. 
cThe sample mean is always close to the population mean.   
dThe sample mean is always smaller than the population mean.   
          
2The sampling distribution of x̅ is approximately normal if   
athe distribution of x is skewed.      
bthe distribution of x is approximately symmetric    
cthe sample size is large enough.      
dthe sample size is small enough.      
          
3There is a population of six families in a small neighborhood:  Albertson, Benson, Carlson, Davidson, Erikson, and Fredrickson.  You plan to take a random sample of n=3 families (without replacement).  The total number of possible sample is _____.
 
 
a6        
b12        
c18        
d20        
          
4The mean daily output of an automobile manufacturing plant is μ = 520 cars with standard deviation of σ = 14 cars.  In a random sample of n = 49 days, the probability that the sample mean output  of cars (x̅) will be within ±3 cars from the population mean is _________.
 
 
a0.9876        
b0.9544        
c0.9266        
d0.8664        
          
5In the population of IUPUI undergraduate students 38 percent (0.38) enroll in classes during the summer sessions.  Let  p̅ denote the sample proportion of students who plan to enroll in summer classes in samples of size n = 200 selected from this population.  The expected value of the sample proportion, E(p̅), is _______.
 
 
 
a0.38        
b0.28        
c0.25        
d0.18        
          
6In the previous question, the standard error of the sampling distribution of p̅ is, se(p̅)=_______.
a0.0343        
b0.0297        
c0.0248        
d0.0221        
          
7The expression       
  
 
  
 
    
      
 Means:    
aOnce you take a specific sample and calculate the value of x̅, the probability that the value of x̅ you just calculated is within ±1.96 σ/√n from μ is 0.95.
 
bIn repeated samples, the probability that x̅ is within ±1.96 σ/√n from μ is 0.95. 
cOnce you take a specific sample and calculate the value of  x̅, you are 95 percent certain that the value you calculated is μ.
 
dIn repeated samples, you are 95 percent certain that the value of x̅ is μ.  
          
8As part of a course assignment to develop an interval estimate for the proportion of IUPUI students who smoke tobacco, each of 480 E270 students collects his or her own random sample of n=400 IUPUI students to construct a 95 percent confidence interval.  Considering the 480 intervals constructed by the E270 students, we would expect ________ of these intervals to capture the population proportion of IUPUI students who smoke tobacco.
 
 
 
 
a480        
b456        
c400        
d380        
          
9Assume the actual population proportion of IUPUI students who smoke tobacco is 20 percent (0.20).  What proportion of sample proportions obtained from random samples of size n=300 are within a margin of error of  ±3 percentage points (±0.03) from the population proportion?
 
 
a0.8064        
b0.8472        
c0.8858        
d0.9050        
          
10To estimate the average number of customers per business day visiting a branch of Fifth National Bank, in a random sample of n = 9 business days the sample mean number of daily customer visits is x̅ = 250 with a sample standard deviation of s = 36 customers.  The 95 percent confidence interval for the mean daily customer visits is:
 
 
 
a(205, 295)       
b(217, 283)       
c(222, 278)       
d(226, 274)       
          
11In the previous question, how large a sample should be selected in order to have a margin of error of ±5 daily customer visits?  Use the standard deviation in that question as the planning value.
 
a78        
b101        
c139        
d200        
          
12Compared to a confidence interval with a 90 percent confidence level, an interval based on the same sample size with a 99 percent level of confidence:
 
ais wider.        
bis narrower.       
chas the same precision.      
dwould be narrower if the sample size is less than 30 and wider if the sample size is at least 30.
          
13It is estimated that 80% of Americans go out to eat at least once per week, with a margin of error of 0.04 and a 95% confidence level.  A 95% confidence interval for the population proportion of Americans who go out to eat once per week or more is:
 
 
a(0.798, 0.802)       
b(0.784, 0.816)       
c(0.771, 0.829)       
d(0.760, 0.840)       
          
14In a random sample of 600 registered voters, 45 percent said they vote Republican.  The 95% confidence interval for proportion of all registered voters who vote Republican is,
 
a(0.401, 0.499)       
b(0.410, 0.490)       
c(0.421, 0.479)       
d(0.426, 0.474)       
          
15John is the manager of an election campaign.  John’s candidate wants to know what proportion of the population will vote for her.  The candidate wants to know this with a margin of error of ± 0.01 (at 95% confidence).  John thinks that the population proportion of voters who will vote for his candidate is 0.50 (use this for a planning value).    How big of a sample of voters should you take?
 
 
 
a9,604        
b8,888        
c5,037        
d1,499        
          
16If the candidate changes her mind and now wants a margin-of-error of ± 0.03 (but still 95% confidence),
aJohn could select a different sample of the same size, but adjust the error probability. 
bJohn should select a larger sample.     
cJohn should select a smaller sample.     
dJohn should inform the candidate that margin of error does not impact the sample size. 
          
17In a test of hypothesis, which of the following statements about a Type I error and a Type II error is correct:
 
aType I:    Reject a true alternative hypothesis.Type II:  Do not reject a false alternative hypothesis.
bType I:    Do not Reject a false null hypothesis.Type II:  Reject a true null hypothesis. 
cType I:    Reject a false null hypothesis.  Type II:  Reject a true null hypothesis. 
dType I:    Reject a true null hypothesis.Type II:  Do not reject a false null hypothesis.
          
18You are reading a report that contains a hypothesis test you are interested in.  The writer of the report writes that the p-value for the test you are interested in is 0.0831, but does not tell you the value of the test statistic.  Using α as the level of significance, from this information you ______
 
 
adecide to reject the hypothesis at α = 0.10, but not reject at α = 0.05.  
bcannot decide based on this limited information.  You need to know the value of the test statistic.
cdecide not to reject the hypothesis at α = 0.10, and not to reject at α = 0.05  
ddecide to reject the hypothesis at α = 0.10, and reject at α = 0.05   
          
19Linda works for a charitable organization and she wants to see whether the people who donate to her organization have an average age over 40 years.  She obtains a random sample of n = 180 donors and the value of the sample mean is x̅ = 42 years, with a sample standard deviation of s = 18 years.  She wants to conduct the test of H: μ ≤ 40  with a 5% level of significance.  She should reject H if the value of the test statistic is _____ 
 
 
 
 
aless than the critical value.      
bgreater than the critical value.      
cmore than two standard errors above the critical value.    
dequal to the critical value.      
          
20Now she performs the test and obtains the test statistic of TS = ______,  
a1.49 and does not reject H₀.  She concludes that the average age is not over 40.  
b1.49 and rejects H₀.  She concludes that the average age is over 40.   
c1.74 and does not reject H₀.  She concludes that the average age is not over 40.  
d1.74 and rejects H₀.  She concludes that the average age is over 40.   
          
21The probability value for Linda’s hypothesis test is ______.   
a0.0207        
b0.0409        
c0.0542        
d0.0681        
          
22The Census Bureau’s American Housing Survey has reported that 80 percent of families choose their house location based on the school district.  To perform a test, with a probability of Type I error of 5 percent, that the population proportion really equals 0.80, in a sample of 600 families 504 said that they chose their house based on the school district.  The null hypothesis would be rejected if the sample proportion falls outside the margin of error.  The margin of error for the test is:
 
 
 
 
a0.039        
b0.032        
c0.025        
d0.020        
          
23The probability value for the hypothesis test in the previous question is:  
a0.0026        
b0.0071        
c0.0142        
d0.0224        
          
24Given the following sample data, is there enough evidence, at the 5 percent significance level, the population mean is greater than 7?
 
          
   x      
   9      
   2      
   15      
   17      
   8      
   11      
   13      
   5      
          
 Compute the relevant test statistic.     
aThe test statistic is 1.683 and the critical value is 1.895. Do not reject the null hypothesis and conclude that the population mean is not greater than 7.
 
bThe test statistic is 1.683 and the critical value is 1.895. Reject the null hypothesis and conclude that the population mean is greater than 7.
 
cThe test statistic is 2.432 and the critical value is 2.365. Reject the null hypothesis and conclude that the population mean is greater than 7.
 
dThe test statistic is 2.432 and the critical value is 1.895. Reject the null hypothesis and conclude that the population mean is not greater than 7.
 
          
 Next SIX questions are based on the following regression model   
 In a regression model relating the price of homes (in $1,000) as the dependent variable to their size in square feet, a sample of 20 homes provided the following regression output.  Some of the calculations are left blank for you to compute.
 
 
          
 SUMMARY OUTPUT       
 Regression Statistics       
 Multiple R0.7760      
 R Square        
 Adjusted R Square0.5801      
 Standard Error       
 Observations20      
          
 ANOVA        
  dfSSMSFSignificance F  
 Regression1  27.249375.78E-05   
 Residual1813960.49      
 Total1935094.63      
          
  CoefficientsStd Errort StatP-valueLower 95%Upper 95% 
 Intercept15.847925.06650.6320.5352-36.81568.511  
 Size (Square Feet)0.06950.0133 5.79E-050.0416   
          
          
25The model predicts that the price of a home with a size of 2,000 square feet would be ______ thousand.
a$148.70        
b$154.80        
c$159.50        
d$164.30        
          
26The sum of squares regression (SSR) is:     
a49055.12        
b35094.63        
c21134.14        
d13960.49        
          
27The regression model estimates that _____% of the variation in the price of the home is explained by the size of the homes.
 
a60.20%        
b65.60%        
c71.50%        
d77.20%        
          
28The standard error of the regression (standard error of estimate) is ______.  
a30.634        
b33.698        
c27.849        
d24.067        
          
29The value of the test statistic to test the null hypothesis that property size does not influence the price of the property is ______.
 
a4.348        
b5.226        
c6.391        
d6.982        
          
30The margin of error to build a 95% confidence interval for the slope coefficient that relates the price response to each additional square foot is _______.
 
a0.042        
b0.032        
c0.034        
d0.028        
          
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