STAT MISC Milestone 1
1
Sam counts how many people came to the local political meeting. He counts 72 people, but forgot about the 4 people sitting behind him.
The percent error in his calculation is __________.
•
50%
•
-5.3%
•
5.6%
•
-2.8%
RATIONALE
Recall that the p...
STAT MISC Milestone 1
1
Sam counts how many people came to the local political meeting. He counts
72 people, but forgot about the 4 people sitting behind him.
The percent error in his calculation is __________.
50%
-5.3%
5.6%
-2.8%
RATIONALE
Recall that the percent error is equivalent to the absolute difference divided by the actual value.
If the actual number of people was 76, and the observed number of people was only 72, then the absolute error is:
So we calculate the percentage error to be:
CONCEPT
Absolute Change and Relative Change
2
A sports trainer is going to do an experiment on the effect of Vitamin D supplements and his athletes. He randomly assigns all of his patients to either take Vitamin D supplements or take a placebo. What type of experimental design does this situation illustrate?
Completely Randomized
Matched-Pair
Simple Random
Randomized Block
RATIONALE
Since all athletes are assigned treatment or control for vitamin D randomly without considering other factors, this is called a completely randomized design.
CONCEPT
Completely Randomized Design
3
In a survey of small business owners, a response to which of the following questions would be qualitative?
How long have you owned a business?
How much did your business have in profits last year?
How many businesses do you own?
What type of business do you own? RATIONALE
All the other options are numeric measures and can be used in arithmetic.
The type of business you have is simply a descriptive measure and is therefore qualitative.
CONCEPT
Qualitative and Quantitative Data
4
In a bolt-manufacturing factory, it is estimated that 6% of the bolts being manufactured will be defective, with a 3% margin of error.
Choose the statement that correctly describes the confidence interval.
The percentage of defective bolts is between 3% and 9%.
The percentage of defective bolts is 6% or more.
The percentage of defective bolts is 6% or less.
The percentage of defective bolts is between 3% and 6%.
RATIONALE
Recall for a confidence interval, we take the point estimate +/- margin of error. Using this framework we take the point estimate of 6%, then add and subtract the margin of error, 3%.
This gives us a CI of 3% to 9%.
CONCEPT
Margin of Error
5
In a study to assess the risk of obesity with the amount of time exercised per
week, researchers matched each patient, in a sample of 500 people who are obese, with a person of the same ethnicity, gender, and age (along with other similar characteristics) who is not obese. The researchers asked the patients and their matches a series of questions, and then tracked eating and exercise habits regularly for several years.
Which type of statistical study are the researchers conducting?
Prospective study
Case-control study
Designed experiment
Retrospective study
RATIONALE
Since the study collected information on people over several years moving forward, it is a prospective study design.
CONCEPT
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