Descriptive Statistics

Question 1

What are descriptive statistics?

Answer 1

The use of tables graphs and summaty statistics to analyse data

Question 2

What does the temr mesures of central tendency refer to?

Answer 2

Any measure which calculates anavarage value within a set of data.

Question 3

How is mean callculated
(+ strengths and limitations)

Answer 3

Total of all values divided by no. of values
Strength
Makes use of all values-most sensitive of MCT
LImitation
Influenced by outliers- Can be unrepresentative

MCT- Measure of cental tendency.

Question 4

How is median callculated
(+ strengths and limtiations)

Answer 4

Arrange data from lowest to highest and find the central value.
Strength
Not affected by extreme scores-Good for ordinal data.
Limitation
Doesnt use all data-Not as sensitive.

Question 5

how is mode calculated?
(+ strength and limitations)

Answer 5

Most frequent occuring value in a set of data.
Strength
useful for nominal data(data in categories).
LImitiation
not useful when there are several modes.

Question 6

What are measures of dispersion?

Answer 6

Any measure that calculates the variation in a set of data.

Question 7

How is range calculated and what are the strengths and limitations?

Answer 7

Minus the lowest score from the highest score
Strength – easy to calculate.
Limitation – affected by extreme values, does not use all data.

Question 8

How is standard deviation calculated and what are the strengths and limitations?

Answer 8

The square root of the variance calculate SD.
A low SD means that more data is clustered close to the mean hence there is less data spread.
Strength – precise, measure, or values are taking into account.
Limitations – difficult to calculate, affected by extreme values.

Question 9

When are bar charts used

Answer 9

When Data has been divided into categories.
The bars do not talk to each other, which shows that we are dealing with separate conditions.

Question 10

When are histograms used?

Answer 10

When dealing with continuous data rather than discreet.
The boys touch each other, unlike in bar charts

Question 11

When are scattergrams used?

Answer 11

To show associations between covariables rather than differences.

Question 12

What is normal distribution?

Answer 12

A symmetrical pattern of frequency data that forms a bell-shape pattern.

Question 13

What is a skewed distribution?

Answer 13

A spread of frequency data that is not symmetrical instead the data or cluster to one end.
There are two types of these:positive skew, negative skew

Question 14

What is a positive skew?

Answer 14

Most of the distribution of data is concentrated on the right.

Question 15

What is a negative skew?

Answer 15

Most of the data distributed is concentrated on the left.