Statistics

Question 1

How do you calculate altered averages?

Answer 1

Set up before and after equations

Question 2

Whats the formula for average

Answer 2

Sum of terms/ number of terms = average

Question 3

What is the formula for weighted average?

Answer 3

[ Weight (value) + weight (value) ] / sum of the weights = weighted average

Question 4

What is the weighted average short cut?

Answer 4

Subtract the largest amount in common to every quantity in your equation

Solve what remains

Add that solution to the amount that was subtracted

Question 5

What is the law of weighted averages?

Answer 5

A weighted average of two values is always drawn closer to the heavier or more frequently occurring term

Question 6

What is the median?

Answer 6

The middle term in a set of numbers ordered from least to greatest

Question 7

How do you find the median of an even number of terms?

Answer 7

Put the terms in order and find the average of the two middle terms

Question 8

How do you solve a fluctuating median problem?

Answer 8

Set up a t-chart and plug potential options for that unknown element into the set

Question 9

How should you approach problems that involve the mean and median of a set of numbers?

Answer 9

Plug the info that youve been given into the average formula

Then simplify

Question 10

What are evenly spaced number sets ?

Answer 10

Any set of numbers in which the gaps between the terms are the same

Question 11

What is true of the mean (average) of evenly spaced number sets?

Answer 11

The mean always equals the median

The average of the first and last terms equals the mean and median of the entire set

Question 12

What is always true of consecutive number sets ?

Answer 12

The mean of a set with an odd number of terms will always be an integer

Question 13

What is standard deviation?

Answer 13

How far each number in the number set is away from the average

Question 14

Whats a small standard deviation indicate?

Answer 14

The numbers in a set are closely bunched around the mean

Question 15

If all numbers in a set are the same what is the standard deviation?

Answer 15

0

Question 16

Whats an easy way to approximate standard deviation?

Answer 16

Think of it as the average difference from the mean

Find the mean of the set
Find the absolute difference between each number and the mean
Average up those differences

Question 17

How do you precisely calculate standard deviation?

Answer 17

Calculate the number set mean 
Find the absolute differences of the numbers and the mean 
Square those differences 
Average the squares 
Find the square root of the average

Question 18

What is a number that falls within a standard deviation ? give an example.

Answer 18

Numbers less than or equal to a certain standard deviation from the mean

I.e.

If standard deviation is 4.0 and the mean is 20

Numbers +- (16 to 24) of 20 are within that standard deviation

Question 19

What is variance?

Answer 19

The square of the standard deviation

Question 20

If you have a variance what should you do to that number to find the standard deviation ?

Answer 20

Take its square root

Question 21

What must happen to a set for the standard deviation to decrease?

Answer 21

The numbers are brought closer to the mean

Question 22

What must happen to a set for the standard deviation to increase?

Answer 22

The numbers are brought further from the mean

Question 23

What happens to a sets standard deviation when you multiply each number in a set by the same amount?

Answer 23

The standard deviation will increase

Question 24

What happens to a sets standard deviation when you divide each number in a set by the same amount?

Answer 24

The standard deviation will decrease

Question 25

What happens to standard decimal if a number is either added or subtracted to each number in the set?

Answer 25

Standard deviation remains unchanged

Question 26

When does standard deviation equal to 0?

Answer 26

When all numbers in the set are the same

When all numbers in the set are equal to the mean

Question 27

What happens when you add a value that is equal to the mean to a number set?

Answer 27

The standard deviation is lowers

Question 28

What is the key to solving maximization problems?

Answer 28

Consider the opposite possibility

Question 29

How do you find the range of a number set?

Answer 29

Calculate the difference between the largest and smallest value

Question 30

What happens of each term in a set is increased but the number of terms remains the same?

Answer 30

The mean must increase

Question 31

What happens when each term in a set is increased by the same amount ?

Answer 31

The median must increase

Question 32

What happens to the standard deviation when you add numbers that equal the mean to the number set ?

Answer 32

The standard deviation decreases

Question 33

Weighted averages fall between…?

Answer 33

The largest and smallest values being averaged