Mesures Of Central Tendanct And Dispersion

Question 1

Define Central tendency

Answer 1

Where the average is in a set of data

Question 2

What are the 3 measures of central tendency

Answer 2

• Mean
• Median
• Mode

Question 3

How do you calculate the mean?

Answer 3

Add up all the values then divide them by the amount of values there are.

Question 4

How do you calculate the median

Answer 4

Order the data set then find the middle value from the data

Question 5

How do you find the mode

Answer 5

Find the most common/ recurring value on the data set

Question 6

Strength and weakness of using mean?

Answer 6

+ Most sensitive as it includes all the values in the data set so its more representative

• easily distorted by extreme values

Question 7

Strength and weakness of using median

Answer 7

+ Extreme scores do not affect it
+ Easily calculated

• Less sensitive than mean because it ignores the lower/ higher values
• Extreme values may be useful

Question 8

Strength and weakness of using Mode

Answer 8

+ Very easy to calculate
+ The only option for categorised data

• Can be unrepresentative
• When there’s more than one / no modes it’s not useful

Question 9

What are the 2 types of descriptive statistic :

Answer 9

• Measures of central tendency

- Measure of dispersion

Question 10

Define measures of dispersion

Answer 10

It tells us the variability that there is within the data

Question 11

What are the two ways to display measures of dispensation

Answer 11

• Range

- Standard deviation

Question 12

Explain range + how to calculate it

Answer 12

Most basic measure of dispensation and tells us the difference between the highest and lowest value in the data set.

Question 13

Explain standard deviation

Answer 13

Sensitive measures of dispersion and tells us how spread out the data is around the mean

Question 14

How is standard deviation displayed and what des it mean

Answer 14

Shown as a single number

Represents how close on average the data is from the mean

The higher the number (3>) the further away it is form the mean = not all ppts were affected by the IV the same & anomalous value

The lower the number = tightly clustered around the mean

Question 15

Strength and weakness of using range

Answer 15

+Easy to calculate

• Unrepresentative because only the 2 highest/lower values are taken not account
• Doesn’t show if its grouped around the mean

Question 16

Strength and weakness of using Standard deviation

Answer 16

+ More precise because it includes all values within the calculation

• Extreme values may not be revealed
• can be distorted by extreme values