Reference no: EM13923743
1. Peak expiratory flow (PEF) is a measure of a patient's ability to expel air from the lungs.
Patients with asthma or other respiratory conditions often have restricted PEF.
The mean PEF for children free of asthma is 306. An investigator wants to test whether children with chronic bronchitis have restricted PEF.
A sample of 40 children with chronic bronchitis is studied and their mean PEF is 279 with a standard deviation of 71.
Is there statistical evidence of a lower mean PEF in children with chronic bronchitis?
Run the appropriate test at α=0.05.
2. Consider again the study in Problem 1, a different investigator conducts a second study to investigate whether there is a difference in mean PEF in children with chronic bronchitis as compared to those without.
Data on PEF are collected and summarized below.
Based on the data, is there statistical evidence of a lower mean PEF in children with chronic bronchitis as compared to those without? Run the appropriate test at α =0.05.
|
Group
|
Number of Children
|
Mean PEF
|
Std Dev PEF
|
|
Chronic Bronchitis
|
25
|
281
|
68
|
|
No Chronic Bronchitis
|
25
|
319
|
74
|
A clinical trial is run to assess the effects of different forms of regular exercise on HDL levels in persons between the ages of 18 and 29.
Participants in the study are randomly assigned to one of three exercise groups - Weight training, Aerobic exercise or Stretching/Yoga - and instructed to follow the program for 8 weeks.
Their HDL levels are measured after 8 weeks and are summarized below.
|
Exercise Group
|
N
|
Mean
|
Std Dev
|
|
Weight Training
|
20
|
49.7
|
10.2
|
|
Aerobic Exercise
|
20
|
43.1
|
11.1
|
|
Stretching/Yoga
|
20
|
57.0
|
12.5
|
Is there a significant difference in mean HDL levels among the exercise groups?
Run the test at a 5% level of significance. HINT: SSerror = 7286.5.
|
Create portfolio with an expected return
: You have $21,000 to invest in a stock portfolio. Your choices are Stock X with an expected return of 10 percent and Stock Y with an expected return of 12.5 percent. If your goal is to create a portfolio with an expected return of 10.95 percent, how m..
|
|
It systems that have affected business
: Identify five different IT systems that have affected business in the past few years. For each system, briefly note the following: A name for the system
|
|
When discounting cash flows
: When discounting cash flows:
|
|
Net present value and payback
: You are contemplating the purchase of a new $1,840,000 computer-based dairy cow feeding system. The system will be depreciated straight line over its ten year life and have no value at the end of its life. You will earn $530,000 per year from additio..
|
|
Apply standard deviation on sampling
: A sample of 40 children with chronic bronchitis is studied and their mean PEF is 279 with a standard deviation of 71.
|
|
Discuss the limitations of ratio analysis
: Discuss the limitations of ratio analysis. In a summary explain the limitations of ratio analysis to help me with a project. I need good details, with well explained limitations please.
|
|
Calculate the required ending-wealth value for the portfolio
: Calculate the required ending-wealth value for this portfolio. Calculate the value of the required floor portfolios at the end of Years 1, 2, and 3.
|
|
Farm will require an initial investment
: Archer Daniels Midland Company is considering buying a new farm that it plans to operate for 10 years. The farm will require an initial investment of $11.80 million. This investment will consist of $2.70 million for land and $9.10 million for trucks ..
|
|
Current place of employment or an organization
: Explain this use in your current place of employment or an organization you are familiar with. Describe concerns with properly controlling this flow, including keeping it safe from unauthorized use.
|