8- Formulas

Question 1

odd number of scores

• List from Lowest to Highest
• It’s the Middle score

Ex., (10, 11, 12, 13, 14. )____. = 12

Even number of scores:

• List from lowest to highest
• Add the middle 2 scores and divide by two

Example, 2, 3, 5, 8, 10, 12, = 5+8/2 = 6.5

Answer 1

Median

Question 2

The distance between the Largest score and the “Smallest” score plus 1

A crude, unreliable measure of variability because:
-Does not consider ALL the scores in the distribution

Calculate:
Ex. 1; 1, 4, 5, 8, 9, 10

10 - 1 + 1 = 10

Ex. 2: 10, 15, 20, 25, 30, 35, 40

40- 10+ 1 = 31

Answer 2

Range

Question 3

The most commonly appearing data points

Can be more than one

Answer 3

Mode

Question 4

P(event) =. # of outcomes classified as the event/total number of Possible outcomes

The probability of event A, p(A), Is the ratio of the number of outcomes that include event K to the total number of possible outcomes

Example What is the probability that a selected Person has a birthday in October, assume 365 days in a year?
Step 1: how many chances are there to have a birthday in a year?

Step 2: how many chances are there to have a birthday in October?

Step 3: the probability that a randomly selected person has a birthday in October is:
P (October birthday) = 31/365 = 0.0849

Answer 4

Probability