Probability and Data Facts

Question 1

If P(A) = x, what is P(not A)?

Answer 1

1 - x

Question 2

If two events are independent, how can we find P(A∩B)?

Answer 2

P(A) x P(B)

Question 3

If two events are mutually exclusive what’s P(A ∩ B)?

Answer 3

0

Question 4

What is the probability of something that is certain?

Answer 4

1

Question 5

What is the probability of something that is impossible?

Answer 5

0

Question 6

What is the sum of probabilities of all mutually exclusive events?

Answer 6

1

Question 7

When you go along branches in a probability tree diagram what do you do with the probabilities?

Answer 7

Multiply them

Question 8

When you combine branches in a probability tree diagram what do you do with the probabilities?

Answer 8

Add them

Question 9

In a probability tree diagram if you remove an object and do not replace it how does the next denominator change?

Answer 9

It decreases by 1.

Question 10

In a probability tree diagram if you remove an object and do then replace it how does the next denominator change?

Answer 10

It stays the same

Question 11

If I toss two coins how many ways are there to get exactly one head and one tail?

Answer 11

Two: HT and TH

Question 12

In set notation what does the union A U B represent?

Answer 12

A or B or both

Question 13

In set notation what is meant by the complement of A which is A’?

Answer 13

Not A

Question 14

In set notation what does the intersection A ∩ B represent?

Answer 14

A and B

Question 15

In set notation what represents Not A?

Answer 15

The complement: A’

Question 16

In set notation what represents A and B?

Answer 16

The intersection: A ∩ B

Question 17

In set notation what represents A or B or both?

Answer 17

The union: A U B

Question 18

How do we calculate interquartile range?

Answer 18

Upper quartile minus lower quartile

Question 19

How do we calculate the range of a set of numbers?

Answer 19

Maximum value minus minimum value

Question 20

How do we find the median of a set of numbers?

Answer 20

Write them in order to find the middle number

Question 21

How do we find the mean of a set of numbers?

Answer 21

Add them up and divide by how many numbers there are.

Question 22

In a set of 19 numbers, which number is the lower quartile?

Answer 22

The fifth number

Question 23

On a box plot, what does the vertical line inside the box represent?

Answer 23

The median

Question 24

What does mode or modal value mean?

Answer 24

The most common / most frequent value

Question 25

In a grouped frequency table where x represents midpoint and f represents frequency what formula can we use to find an estimate of the mean?

Answer 25

Sum of (f times x) divided by sum of f

Question 26

In a histogram how do you work out frequency density?

Answer 26

Frequency density = frequency / class width

Question 27

Cumulative frequency is plotted against which point of each group?

Answer 27

The Endpoint

Question 28

In a histogram what does the area of each bar represent?

Answer 28

Frequency

Question 29

How do you calculate the estimate of the mean for a grouped frequency table?

Answer 29

Total(frequency x midpoint) ÷ total (frequency)

Question 30

How would we describe the correlation going from the bottom left to the top right of a scatter graph?

Answer 30

Positive

Question 31

How would we describe the correlation going from the top left to the bottom right of a scatter graph?

Answer 31

Negative

Question 32

When a scatter graph has strong correlation what does that mean?

Answer 32

The points all lie near the line of best fit

Question 33

When a scatter graph has weak correlation what does that mean?

Answer 33

The points do not all lie near the line of best fit

Question 34

On a scatter graph if there is no line of best fit how do we describe the correlation?

Answer 34

No correlation