Further Stats Year 1 Word Scramble
|
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
| Question | Answer |
| How do you work out E(X) of a discrete random variable? | Σ (x P(X=x)) |
| How do you work out E(X²) of a discrete random variable? | Σ (x² P(X=x)) |
| Var(X) = | E(X²) - E(X)² |
| E(aX+b) = | aE(X)+b |
| E(X+Y) = | E(X) + E(Y) |
| Var(aX+b) = | a²Var(X) |
| X~Po(λ). P(X=x) = | (e^-λ λ^x) / x! |
| What are the three condition needed for the Poisson distribution to be suitable? | Events occur: independently, singly (in space or time), at a constant average rate |
| X~Po(5), Y~Po(6), X+Y~Po(?) | 11 |
| X~Po(λ). E(X)= | λ |
| X~Po(λ). Var(X)= | λ |
| X~B(n,p). E(X)= | np |
| X~B(n,p). Var(X)= | np(1-p) |
| X~B(100,0.02) can be approximated by... because... | X~Po(2) as n is large and p is small |
| What are the hypothesise for a hypothesis test for the mean of a Poisson distribution? | H0- λ=(some value) H1- λ >/</≠ (some value) |
| How many critical regions/values does H1: λ > 3 have? | 1 region 1 value |
| How many critical regions/values does H1: λ ≠ 3 have? | 2 regions 2 values |
| What are the typical hypothesise for a chi sqaured test? | H0- There is no difference between the observed and the theoretical distribution H1- There is a difference between the observed and the theoretical distribution |
| What does a goodness of fit tell us? | How well an observed frequency fits to a known distribution |
| How do we calculate goodness of fit? | Σ (Oi² / Ei) - N |
| χ² can approximate X² as long as... | None of the expected values are below 5 |
| Degrees of freedom= | No. cells (after combining) - no. constraints |
| What are the 2 typical constraints? | 1) A limited sample was used 2) A value was calculated beforehand |
| What dictates which χ² you use? | Degrees of freedom |
| X² > χ² then... | reject H0 |
| X² < χ² then... | accept H0 |
| How do you work out expected values of a contingency table? | (row total x column total) / grand total |
| How do you work out degrees of freedom of a contingency table? | No. cells remaining after removing last row and column |
Created by:
XanderMoore
Popular Math sets