More general Y1 stats

If a grouped frequency table is given, and the variable type is continuous, what is the class width for the row 32-34 if the above row is 30-31 and the below row is 35-40?

the values have been rounded to the nearest integer

The upper bound is 34.5

The lower bound is 31.5

The class width is 3

When would be best to use the mode as a measure of central tendency?

When the data given is qualitative

When would be best to use the median as a measure of central tendency?

When there are extreme values in the data

When would be best to use the mean as a measure of central tendency?

When you want a true value for the measure of central tendency

How do you find the position of the lower quartile for discrete data?

n/4 : if this is an integer then go halfway between this position and the next (average / midpoint of those two values),

if this is a decimal, round up to the next integer/position and choose this

What are you assuming when using linear interpolation?

That data is distributed evenly within the classes (thus data is continuous)

What do percentiles do?

Split the data into 100 parts

True or false? You should use the rounding rule for discrete data quartile positions when finding a percentile of discrete data?

True

What is (x - x bar) ?

The difference between every value and the mean

How can you use your calculator to find summary stats like variance?

Use the statistics section, enter your list (and a list of corresponding frequencies if applicable)

Define:

Random variable

Sample space

Probability distribution

Probability mass function

Discrete uniform distribution

Random variable : the value of the variable depends on the outcome of a random event

Sample space : the set of all possible values of a random variable

Probability distribution : describes the probability of any outcome in the sample space

Probability mass function : a way of describing the probability distribution e.g. : P(X=x) = 1/6 x=1,2,3,4,5,6

Discrete uniform distribution : when the probability of every element of the sample space is the same

Besides a probability mass function, how can probability distributions be shown?

With a table,

With a graph

What is the best notation for a probability mass function?

What are the 4 requirements to describe a random variable using a Binomial distribution?

T : Two possible outcomes

I : Independent trials

n : A fixed number of trials

S : a fixed probability of success