1. Last year you received an average of 129.2 complaints (i.e., individual items to be fixed under warranty) per new car sold, with a standard deviation of 42.1 com- plaints based on 3,834 new cars sold. This year you have set up a quality assurance program to fix some of these problems before the car is delivered. So far this year, you have had an average of just 93.4 com- plaints per new car sold with a standard deviation of 37.7, based on 74 cars sold so far. a. To see if your new quality assurance program is working, what hypothesis testing method would you use? b. Identify the populations, samples, and hypotheses. c. Perform a two-sided test at the 5% level and report the results.2. A group of experts has rated your winery’s two best varietals. Ratings are on a scale from 1 to 20, with higher numbers being better. The results are shown in Table 10.7.6. Is this a paired or unpaired situation? Why? Find the average rating for each varietal and the average difference in ratings (Chardonnay minus Cabernet Sauvignon). Find the appropriate standard error for the average difference. Find the 95% two-sided confidence interval for the mean difference in rating. Test to see if the average ratings are significantly different. If they are significantly different, which varietal is superior? Write a paragraph interpreting the results of this test. 3. To help you decide which of your two current suppliers deserves the larger contract next year, you have rated a random sample of plastic cases from each one. The data are a composite of several measurements, with higher numbers indicating higher quality (Table 10.7.11). a. Find the average quality for each supplier. b. Find the standard deviation of quality for each supplier. c. Find the average difference in quality (International minus Custom) and its standard error. d. Find the two-sided 95% confidence interval for the quality difference. e. Is there a significant difference in quality? How do you know? 4.Refer to the employee
database in Appendix A. View this data set as a random sample from a much
larger population of employees.
3.Test to see if the
gender ratio differs significantly from 50%.
4.Test to see if the
population mean annual salary for men differs from that for women.
statistics.docx
Unformatted Attachment Preview
38. Last year you received an average of 129.2 complaints (i.e., individual items to be fixed under
warranty) per new car sold, with a standard deviation of 42.1 com- plaints based on 3,834 new cars sold.
This year you have set up a quality assurance program to fix some of these problems before the car is
delivered. So far this year, you have had an average of just 93.4 com- plaints per new car sold with a
standard deviation of 37.7, based on 74 cars sold so far.
a. To see if your new quality assurance program is working, what hypothesis testing method would you
use?
b. Identify the populations, samples, and hypotheses.
c. Perform a two-sided test at the 5% level and report
the results.
41. A group of experts has rated your winery’s two best varietals. Ratings are on a scale from 1 to 20,
with higher numbers being better. The results are shown in Table 10.7.6.
a. Is this a paired or unpaired situation? Why?
b. Find the average rating for each varietal and the average difference in ratings (Chardonnay minus
Cabernet Sauvignon).
c. Find the appropriate standard error for the average difference.
d. Find the 95% two-sided confidence interval for the mean difference in rating.
e. Test to see if the average ratings are significantly different. If they are significantly different, which
varietal is superior?
f. Write a paragraph interpreting the results of this test.
g. 46. To help you decide which of your two current suppliers deserves the larger contract next year, you
have rated a random sample of plastic cases from each one. The data are a composite of several
measurements, with higher numbers indicating higher quality (Table 10.7.11).
a. Find the average quality for each supplier.
b. Find the standard deviation of quality for each supplier.
c. Find the average difference in quality (International minus Custom) and its standard error.
d. Find the two-sided 95% confidence interval for the quality difference.
e. Is there a significant difference in quality? How do you know?
Refer to the employee database in Appendix A. View this data set as a random sample from a much larger
population of employees.
3.Test to see if the gender ratio differs significantly from 50%.
4.Test to see if the population mean annual salary for men differs from that for women.
…
Purchase answer to see full
attachment
Recent Comments