Measures of Central Tendency/Measure of Variability

Question 1

What is a mode?

Answer 1

score that occurs most frequently

• It is possible to have more than one mode
• Disregards N and extreme scores

Question 2

What is a median?

Answer 2

Middle score when data is in rank order
( Lowest – Highest) & Vice Vera

** Vaules of extreme scores do not matter

Question 3

How would you solve a median when the amount of numbers present is even? odd?

Answer 3

For Even: Average the (2) middle socre

For Odd: It will be the middle number

Question 4

What is a mean?

Answer 4

Average of N, reported by one extra decimal place

EXAMPLE: 5.7

Question 5

What may affect the mean?

Answer 5

number, value, and outliers affect a mean

Question 6

What is Variability?

Answer 6

Measure of the spread or dispersion of a data set

Question 7

How do you measure variability?

Answer 7

You measure variability by Variance
Also...
Range
Interquartile Range
Standard Deviation

Question 8

What is Variance?

Answer 8

Average of the squared deviations from the mean

Question 9

What is the formula for Variance?

Answer 9

Variance = __Sum(X-X)^2__

N-1

Question 10

How do you find Standard Deviation?

Answer 10

Square root of the variance

Question 11

What is the formula of Standard Deviation?

Answer 11

SD= square root of [___Sum(X-X^2)____]

N-1

Question 12

Why do we have Degrees of Freedom?

Answer 12

Last point is not free to vary

Question 13

What is the formula for Coefficient of Variation (CoV) ?

Answer 13

CoV= _____Standard Deviation___

Mean