8.14 Test for a significant difference in the variances of the initial white blood cell count between patients who did and patients who did not receive a bacterial culture.
8.15 What is the appropriate test procedure to test for significant differences in mean white blood cell count between people who do and people who do not receive a bacterial culture?
8.18 Compute a 95% CI for the true difference in mean white blood cell count between the two groups.
A 1980 study was conducted whose purpose was to compare the indoor air quality in offices where smoking was permitted with that in offices where smoking was not permitted . Measurements were made of carbon monoxide (CO) at 1:20 p.m. in 40 work areas where smoking was permitted and in 40 work areas where smoking was not permitted. Where smoking was permitted, the mean CO level was 11.6 parts per million (ppm) and the standard deviation CO was 7.3 ppm. Where smoking was not permitted, the mean CO was 6.9 ppm and the standard deviation CO was 2.7 ppm.
a) State the null hypothesis
Null hypothesis: There is no significant difference between the mean CO level in institutions where smoking is permitted and institutions where smoking is not permitted.
b) State the alternative hypotheses
There is a significant difference between the mean CO level in institutions where smoking is permitted and institutions where smoking is not permitted.
c) show the test statistics.
Work areas (1)=40
Work areas 2=40
Standard deviation of work area 1= 11.6
Standard deviation of work area 2= 2.7
Mean of work area 2= 6.9
Mean of work area 1= 7.3
Ho= standard dev1=standard dev2
Ha= standard dev1 does not equal standard dev 2
F test: standard deviation of work area 1^2 / standard deviation of work area 2
DOF= 40-1=39 ( for both)
Critical value = .05
8.25 Test for whether the standard deviation of CO is significantly different in the two types of working environments.
A camera has been developed to detect the presence of cataract more accurately. Using this camera, the gray level of each point (or pixel) in the lens of a human eye can be characterized into 256 gradations, where a gray level of 1 represents black and a gray level of 256 represents white. To test the camera, photographs were taken of 6 randomly selected normal eyes and 6 randomly selected cataractous eyes (the two groups consist of different people). The median gray level of each eye was computed over the 10,000+ pixels in the lens. The data are given in Table 8.14.
8.28 What statistical procedure can be used to test whether there is a significant difference in the median gray levels between cataractous and normal eyes?
* paired t test?
8.29 Carry out the test procedure mentioned in Problem 8.28, and report a p-value.
8.30 Provide a 99% CI for the mean difference in median gray levels between cataractous and normal eyes.
8.39 What is the appropriate test procedure to determine whether there is a systematic difference between the assessments of Doctor A vs. Doctor B?
? chi squared analysis?
* appropriate statistical procedure
8.56 What test can be performed to compare the variances of the two genotype groups?
8.92 What test can be used to compare the mean ln (ERG amplitude) between patients with dominant vs. recessive RP?
Why Work with Us
Top Quality and Well-Researched Papers
We always make sure that writers follow all your instructions precisely. You can choose your academic level: high school, college/university or professional, and we will assign a writer who has a respective degree.
Professional and Experienced Academic Writers
We have a team of professional writers with experience in academic and business writing. Many are native speakers and able to perform any task for which you need help.
Free Unlimited Revisions
If you think we missed something, send your order for a free revision. You have 10 days to submit the order for review after you have received the final document. You can do this yourself after logging into your personal account or by contacting our support.
Prompt Delivery and 100% Money-Back-Guarantee
All papers are always delivered on time. In case we need more time to master your paper, we may contact you regarding the deadline extension. In case you cannot provide us with more time, a 100% refund is guaranteed.
Original & Confidential
We use several writing tools checks to ensure that all documents you receive are free from plagiarism. Our editors carefully review all quotations in the text. We also promise maximum confidentiality in all of our services.
24/7 Customer Support
Our support agents are available 24 hours a day 7 days a week and committed to providing you with the best customer experience. Get in touch whenever you need any assistance.
Try it now!
How it works?
Follow these simple steps to get your paper done
Place your order
Fill in the order form and provide all details of your assignment.
Proceed with the payment
Choose the payment system that suits you most.
Receive the final file
Once your paper is ready, we will email it to you.
No need to work on your paper at night. Sleep tight, we will cover your back. We offer all kinds of writing services.
No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.
Admission Essays & Business Writing Help
An admission essay is an essay or other written statement by a candidate, often a potential student enrolling in a college, university, or graduate school. You can be rest assurred that through our service we will write the best admission essay for you.
Our academic writers and editors make the necessary changes to your paper so that it is polished. We also format your document by correctly quoting the sources and creating reference lists in the formats APA, Harvard, MLA, Chicago / Turabian.
If you think your paper could be improved, you can request a review. In this case, your paper will be checked by the writer or assigned to an editor. You can use this option as many times as you see fit. This is free because we want you to be completely satisfied with the service offered.