Multivariable methods can be used to assess the impact of the independent variable on the dependent variable as long as there are no confounders present
True
False
Peak expiratory flow (PEF) is a measure of a patients 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 are 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 ?=0.05.
When would we reject HO?
Select one:
a. When the answer = 0
b. If the alternative hypothesis is greater
c. If Z = 1.645
d. If Z is < or = -1.645
3. The null hypothesis suggests that there is no change in the observation whereas the research hypothesis suggests that there is a change in the observation
Select one:
True
False
Peak expiratory flow (PEF) is a measure of a patients 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 are 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 ?=0.05.
What is the research or alternative hypothesis?
Select one:
a. H1 >306
b. H1<306
c. H1-=306
6. Multivariable methods can account for variables that are not known during the course of the study?
Select one:
True
False
7.The critical value for Z at the .05 level is
Select one:
a. 1.375
b. 1.645
c. 1.75
d. It varys depending on the outcome variable
8.Peak expiratory flow (PEF) is a measure of a patients 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 are 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 ?=0.05.
9.What is the null hypothesis
Select one:
a. H0 > 306
b. HO < 306
c. HO = 306
10.Two independent samples require a dichotomous outcomes variable
Select one:
True
False
11.The three forms of the research or alternative hypothesis are:
Select one:
a. High, low and neutral
b. Increased, decreased or changed
c. +1, -1, 0
d. Depends on the data given
12.Confounding occurs when the relationship between two variables are influenced by a third variable.
Select one:
True
False
13. Peak expiratory flow (PEF) is a measure of a patients 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 are 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 ?=0.05.
14. Would we reject or accept the HO?
Select one:
a. Accept
b. Reject
c. There is not enough information
15. In linear regression the dependent variable must be dichotomous?
Select one:
True
False
16. A study is run comparing HDL cholesterol levels between men who exercise regularly and those who do not. The data are shown below.
What is the 95% confidence interval for the difference in the mean HDL levels between men who exercise regularly and those who do not?
N Mean std DEV
Yes 40 48.5 12.5
No 125 56.9 11.9
Select one:
a. -12.93 to -3.87
b. 12.93 to -3.87
c. -12.70 to -4.10
d. 12.70 to -4.10