Assessment 4 Research methods and Biopsychology

Question 1

What is an opportunity sample?

Answer 1

Recruitment who are most convenient / easily available at the time of study.

Question 2

What is a strength and a weakness of an opportunity sample?

Answer 2

S- easiest method/least amount of time used.

W- Inevitably biased as sample drawn from a small area.

Question 3

What is a random sample?

Answer 3

Everybody in population has an equal chance of being chosen - lottery method, all in a hat.

Question 4

What is a strength and a weakness of an random sample?

Answer 4

S- unbiased; everyone has an equal chance.

W- Time consuming need a long list and a lot of contact details.

Question 5

What is a stratified sample?

Answer 5

Subgroups within a population eg: boys aged 10-17 and ppts are then randomly selected from the subgroups.

Question 6

What is a strength and a weakness of an stratified sample?

Answer 6

S- More representative than other methods- proportional and randomly selected.
W- very time consuming identifying subgroups.

Question 7

What is a systematic sample?

Answer 7

Sample obtained by using nth term. Numerical interval applied consistently.

Question 8

What is a strength and a weakness of an systematic sample?

Answer 8

S- unbiased as ppts are selected through an objective system.
W- Not truly unbiased unless you select a number using a random method and start with this person.

Question 9

What is a volunteer sample?

Answer 9

Advertising in newspaper, noticeboard or internet.

Question 10

What is a strength and a weakness of an volunteer sample?

Answer 10

S- Access to a wide variety of ppts nay make some more representative/less biased.
W- Ppts biased in other ways - more highly motivated. Volunteer bias.

Question 11

What are the mean, median and mode all a part of?

Answer 11

Measures of central tendency

A descriptive stat that provides information about a ‘typical’ value for a data set.

Question 12

What are the range and standard deviation a part of?

Answer 12

Measures of dispersion

Question 13

What is the mode?

Answer 13

Most frequently occurring value/item in a data set

Question 14

What is the median?

Answer 14

Middle value in a data when the items are place in rank order.

Question 15

What is the mean?

Answer 15

The arithmetic average of a data set.

Add up all numbers and divide by number of items in data set.

Question 16

What is the range?

Answer 16

Difference between highest and lowest item in a data set.

Question 17

What is standard deviation?

Answer 17

Shows the amount of variation in a data set. Assesses spread of data around the mean.

Question 18

Give 1 strength and 1 weakness of the mean.

Answer 18

S - Most sensitive measure, takes account of exact distance between all values of all the data.

W - Sensitivity means it can be easily distorted by an extreme value.

Question 19

Give 1 strength and 1 weakness of the median.

Answer 19

S - Not affected by extreme scores
Can be easier to calculate the mean.

W - Median is not as ‘sensitive’ as the mean because exact values are not reflected in the final calculation.

Question 20

Give 1 strength and 1 weakness of the mode.

Answer 20

S - Unaffected by extreme values
More useful for discrete data.

W - Not a useful way of describing data when there are several modes.
Does not tell us about distribution of values.

Question 21

Give 1 strength and 1 weakness of the range.

Answer 21

S - Easy to calculate

W - Affected by extreme values.
Fails to account for distribution of the numbers

Question 22

Give 1 strength and 1 weakness of the standard deviation.

Answer 22

S - Precise measure of dispesion because it takes all exact values into account.
Not difficult to calculate if you have a calculator.

W - May hide some characteristics of data set (extreme values).