Probability and Data Facts Flashcards
If P(A) = x, what is P(not A)?
1 - x
If two events are independent, how can we find P(A∩B)?
P(A) x P(B)
If two events are mutually exclusive what’s P(A ∩ B)?
0
What is the probability of something that is certain?
1
What is the probability of something that is impossible?
0
What is the sum of probabilities of all mutually exclusive events?
1
When you go along branches in a probability tree diagram what do you do with the probabilities?
Multiply them
When you combine branches in a probability tree diagram what do you do with the probabilities?
Add them
In a probability tree diagram if you remove an object and do not replace it how does the next denominator change?
It decreases by 1.
In a probability tree diagram if you remove an object and do then replace it how does the next denominator change?
It stays the same
If I toss two coins how many ways are there to get exactly one head and one tail?
Two: HT and TH
In set notation what does the union A U B represent?
A or B or both
In set notation what is meant by the complement of A which is A’?
Not A
In set notation what does the intersection A ∩ B represent?
A and B
In set notation what represents Not A?
The complement: A’
In set notation what represents A and B?
The intersection: A ∩ B
In set notation what represents A or B or both?
The union: A U B
How do we calculate interquartile range?
Upper quartile minus lower quartile
How do we calculate the range of a set of numbers?
Maximum value minus minimum value
How do we find the median of a set of numbers?
Write them in order to find the middle number
How do we find the mean of a set of numbers?
Add them up and divide by how many numbers there are.
In a set of 19 numbers, which number is the lower quartile?
The fifth number
On a box plot, what does the vertical line inside the box represent?
The median
What does mode or modal value mean?
The most common / most frequent value
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?
Sum of (f times x) divided by sum of f
In a histogram how do you work out frequency density?
Frequency density = frequency / class width
Cumulative frequency is plotted against which point of each group?
The Endpoint
In a histogram what does the area of each bar represent?
Frequency
How do you calculate the estimate of the mean for a grouped frequency table?
Total(frequency x midpoint) ÷ total (frequency)
How would we describe the correlation going from the bottom left to the top right of a scatter graph?
Positive
How would we describe the correlation going from the top left to the bottom right of a scatter graph?
Negative
When a scatter graph has strong correlation what does that mean?
The points all lie near the line of best fit
When a scatter graph has weak correlation what does that mean?
The points do not all lie near the line of best fit
On a scatter graph if there is no line of best fit how do we describe the correlation?
No correlation
