 (15%) For Applied Management Statistics class you want to know
how college students feel
about the transportation system in
Barcelona.
 What is the population in this study?
 What type of sample would you use and why?
 (25%) A manager of an ecommerce company would like to
determine average delivery time of the products. A sample of 25
customers is taken. The average delivery time in the sample was
four days. Suppose the delivery times are normally distributed with
a standard deviation of 1.2 days.
 Provide a 95 % confidence interval for the mean delivery
time.
 The manager claims that the average delivery time of their
products does not exceed 3 days. Write the null and alternative
hypothesis regarding to the claim of the manager.
 Test the manager’s claim at 95 % confidence level.
 Write the conclusion of your result
 (15%) For an effective parental skill study, a researcher
asked: How many hours do your kids watch the television during a
typical week in Barcelona? The mean of 100 Kids (ages 611) spend
about 28 hours a week in front of the TV. Suppose the study follows
a normal distribution with standard deviation 5.
 Estimate the mean of all kids (ages 611) in Barcelona, using
99% confidence interval. (show all the calculations)
 Write the conclusion of your result
 (25%) A regression analysis has been conducted between the
annual income (in 1000 euros) and the work experience (in years) of
people with 0.05 significance level. The results are summarized
below.
 Define the independent and dependent variables. What can you
say about the correlation between them.
 Interpret R Square.
 Write the regression model and interpret the coefficients.
 Estimate the average annual income of a person who has 15 years
of work experience.
Summary







Table 1.







Regression Statistics






Multiple R

0,93






R Square

0,86






Adjusted R Square

0,82






Standard Error

2,11






Observations

6













Table 2.








df

SS

MS

F

Significance F


Regression

1

107,603

107,603

24,276

0,008


Residual

4

17,730

4,432




Total

5

125,333





Table 3.








Coefficients

Standard Error

t stat

p value

Lower 95%

Upper 95%

Intercept

17,351

3,160

5,491

0,005

8,577

26,124

Variable X 1

1,362

0,276

4,927

0,008

0,595

2,130
