Data handling Flashcards
(14 cards)
How do you draw a sample space diagram?
You put one set of variable on the top, and the other on the side.. You then draw a table, and the probability of a box happening is the 1/ the number of boxes.
How do you work out experimental probability?
If an event isn’t well know, you do experimental probability, to get an estimate of the actual probability. If an event occurs f times in g trials, the experimental probability is f/g.
How do you work out expectation?
If an event has probability p, the expectation is in a trials is ap. E.g. If tossing a coin has probability 1/2, and you toss it 10 times, the expectation = 5
How do you find the probability of an event not happening?
You minus the probability from one.
What are exhaustive events?
Events that cover all possibilities, e.g. Rolling a die and getting an odd or even number
How do you draw a tree diagram?
You draw the number of arms for all the outcomes, and write the probability in each. Then you draw more arms stemming from them, and write the probability on them. You times all the probabilities along a route to get the probability for that end outcome.
What is conditional probability and how does it work?
Conditional probability is where the outcome of one events changes the probability, e.g. Taking a counter out of a bag of 2 black and 3 white counters and not replacing it, then taking another counter.
How does conditional probability affect a tree?
You draw the tree normally, but the probabilities will change the second picking, e.g. You pick a black counter and instead of a 2/5 probability, it will be 1/4 for black again.
How is probability measured?
It is measured in a fraction, on a scale of 1-0. 1 means it will definitely happen, 0 means it is impossible.
How do you find median and mode on a frequency table?
Mode: look on the right hand side, and the row with the highest number is the mode. Median: do the cumulative frequency until you find the group the middle value is in.
How do you find mean from a frequency table?
To find the mean you do the frequency times the value on the left, divided by the frequency.
What are quartiles and how do we find them?
The lower quartile is the value that 25% of the data is below. The upper quartile is the value that 75% of the data is above. To find them you find the median, then take the median out and repeat the process in that half, to find the quartiles.
What is the Inter-Quartile range and how do you find it?
The IQR = UQ-LQ. 50% of the data values lie in that range.
How do you find the cumulative frequency?
You add up all the frequencies so far. It increases with every new row.
