Systematic & Random Errors

Question 1

You want to study whether the number of hours slept on average each week is related to whether a student passes their final exams at university. You are short for time and therefore go and interview subjects on Sunday who have retired (so you are likely to obtain enough subjects) and who attend a regular exercise walking class for retirees. You ask the subjects how many hours of sleep they get on average each week and whether they have a university degree (meaning they have passed university). This is an example of?
Select one:
a. Selection bias 
b. Measurement bias
c. Effectmodification
d. Confounding

Answer 1

a. Selection bias

Question 2

You want to measure weight (kg) of diabetic patients for a study recruited from a clinic in the Illawarra. You take 3 measurements for the first patient on a weighing scale and get weights of 70kg, 85kg, 50kg respectively. The patient’s self report of their weight is 60kg. This is most likely to be what sort of error?
Select one:
a. Random error
b. Systematic error

Answer 2

a. Random error

Question 3

Selection bias is what sort of error?
Select one:
a. Systematic error
b. Random error

Answer 3

a. Systematic error

Question 4

Measurement bias is what kind of error?
Select one:
a. Random error
b. Systematic error

Answer 4

b. Systematic error

Question 5

If two (2) different research assistants are collecting data for your study and one collects coffee consumption by asking the participants in the control group whether they are coffee drinkers (and hence underestimating coffee consumption) and the other assistant collects smoking status in the cases group by looking café receipts (and hence correctly estimating coffee consumption), this is an example of what bias?

a. Measurement bias
b. Selection bias
c. Attrition bias (loss to follow up)
d. Recall bias

Answer 5

a. Measurement bias

Question 6

You measure coffee consumption and it’s association with high blood pressure in a case control study. You measure coffee consumption asking them how much they consumed in the last month. Let’s say those without high blood pressure incorrectly estimated the amount of coffee consumed and those with high blood pressure correctly estimated the amount of coffee consumed. This is an example of what type of bias?

a. Measurement bias
b. Selection bias
c. Attrition bias (loss to follow up)
d. Recall bias

Answer 6

d. Recall bias

Question 7

What type of error is it when there are statistical fluctuations due to precision limitations in data?

Answer 7

Random error.

Question 8

What types of bias occur from systematic errors?

Answer 8

1. Measurement bias

2. Selection bias

Question 9

Why do systematic errors occur?

Answer 9

1. Faulty equipment

2. Flawed experiment/study design

Question 10

What type of bias is it when the groups being studied dont represent the population?

Answer 10

Selection bias.

Question 11

What type of bias is it when there is an error in the measurement of information?

Answer 11

Measurement bias.