P3 shit

Question 1

What is proof by contradiction?

Answer 1

assume the opposite so the statement is true then show why it is false

Question 2

what is a population?

what is a sample?

Answer 2

population is everyone

sample is a portion of people

Question 3

what is a census? pro cons?

Answer 3

a census is when everyone is asked, expensive, non bias, time consuming, difficult to know if you have everyone’s responses

Question 4

what is discrete data?

what is continues data?

Answer 4

discrete data is when data falls into distinct categories e.g
continues data is when you can go into forever increasing levels of accuracy

Question 5

what is qualitive and quantitative?

Answer 5

quantitative is something that is numerical

qualitive is non numerical

Question 6

what is simple random sampling?

Answer 6

assign a number to everyone, pick random numbers, number random generator

Question 7

what is systematic sampling?

Answer 7

picking every so often out of the number, gives unbiased sample

Question 8

what is stratified sampling?

Answer 8

split the items into ratios so a fair amount of items can be selected compared to the size of the samples.

then use systematic or simple random

Question 9

what is quota sampling?

Answer 9

go out and find people to fill the qouta of how many people you wanna question. cost effective, can be biased

Question 10

what is opportunity sampling?

Answer 10

first people you come across, quick easy, biased

Question 11

what is cluster sampling?

Answer 11

when a spread of data is needed, select 5 stores and then question the ppl from there.

Question 12

what is self selection sampling?

Answer 12

people opt in to fill out a questionnaire, cost effective, biased as only people with strong opinions appear to do the survey

Question 13

what is does the middle line in the box in a box plot stand for?

how do you work out the outliers in a box plot?

what do the ‘whiskers’ stand for?

Answer 13

the median

(LQ - 1.5 X IQR) (UQ + 1.5 X IQR)

the lowest point that is not an outlier or the boundary for outliers

Question 14

what do you talk about when comparing box plots?

what can you do with the whiskers when drawing box plots?

Answer 14

consistency, average, highest lowest scores.

Can draw the whisker closer if within the boundary if the next known point is as so, cant draw beyond tho

Question 15

what is the frequency density in a histogram?

Answer 15

the frequency divided by the class width

Question 16

How do you find the UQ? LQ? median?

Answer 16

Median - half top number
LQ - 1/4 the top number
UQ - 3/4 the top number

Question 17

what is the equation for the area of a histogram?

Answer 17

Area = k x frequency

Question 18

how do you work out the median UQ LQ etc when the value is within a range in the histogram table?

Answer 18

the x term on the number line minus the first term divided by the full distance so end term minus first term

then put equal to the culmative frequency in the same format x mins fist divided by last minus first term

Question 19

how do you find the regression value using ur calculator?

How do you find the equation for the regression line?

Answer 19

go to statistics function on your calculator, go to y = a + bx. fill table in, press AC then OPTN then regression calculation

exact same thing, a and b are ur parts of the equation

Question 20

what is interpolation?

what is extrapolation?

Answer 20

interpolation is the range of values that is reliable

extrapolation is values beyond what we have seen and recorded

Question 21

what does A union B mean?

Answer 21

Means A or B or both, so the whole interior venn diagram if it was 2 circles

Question 22

what does A intersection B mean?

Answer 22

A and B, so just where the circles overlap

Question 23

how do you find A union B?

Answer 23

probability of A + probability of B - probability of the intersection

Question 24

what does independent probability mean? formulea?

Answer 24

2 events do not affect one another. so A intersection B = A times B

Question 25

what does mutually exclusive mean? formulea?

Answer 25

when 2 events cant happen at the same time. A intersection B = 0

Question 26

What does p (A I B) mean? formulea?

Answer 26

the probability of A given that B has happened.

Question 27

what does (p') mean? - in probailtiy

Answer 27

The chance of the event p not happening

Question 28

When do u use binomial Pd on the calculator? what do we use binomial Cd (binomial culmative) on the calculator? what is x, n, p on the calculator? When do you use list and variable?

Answer 28

For a particular binomial probability use Pd when x = when x is greater or less than x is number of success you want n is the number of trials p is the probability of success Variable for a single event. List for multiple events

Question 29

what does mu stand for? what does sigma stand for? what does x stand for?

Answer 29

the mean value variance/ standard deviation x is the number you want

Question 30

how much percentage does 1 standard deviation away show? 2? 3?

Answer 30

68% 95% 99.7%

Question 31

what are the values for mu and sigma when we use the standard normal distribution curve?

Answer 31

``` mean (mu) = 0 standard deviation (sigma) = 1 ```

Question 32

what is the equation to transfer from a normal distribution to the standard normal curve?

Answer 32

z = x - mu over sigma

Question 33

how does the inverse normal work when using it in the calculator

Answer 33

the area always always refers to the left hand area so the line you look at and too the left

Question 34

in summary statistics what is the mean?

Answer 34

some of x over n some of numbers over the quantity of numbers

Question 35

what does x bar stand for?

Answer 35

x bar is the mean

Question 36

What is the null hypothesis? What is the alternative hypothesis what is the significance level?

Answer 36

H0, what you think the probability is H1, the argument against it The significance level is the probability of incorrectly rejecting H0

Question 37

when do we do a 1 tail test? | when do we do a 2 tail test?

Answer 37

1 tail when the H1 is above or bellow the H0 2 tail when the H1 is not equal to the H0, u test both above and bellow at the same time, so you half the significance level and do this for both sides

Question 38

what is the critical region? | what is acceptance region?

Answer 38

the region where we can reject the null hypothesis | The region where we fail to reject the null hypothesis

Question 39

how do we set-up a hypothesis test?

Answer 39

start by stating what p is equal to put H0 : p = the probability then H1 : P < the probability Then write assume H0 is true, X swiggly line( is binomally distributed too), bracket, n,p bracket. Compare the answer to the significance level and fail to rejcect H0 or rejct H0 concluding statement, there is insigg or significant evidence to suggest weather etc etc

Question 40

when can we only do less than or equal too? so what we do for both these times?

Answer 40

when binomally distrubting, draw a number line, do 1 minus etc when inverse normal, draw diagram, do 1 minus etc

Question 41

when we do a 2 tailed test how do we know wheather to do great than and equal too or less than and equal to?

Answer 41

depends on the data, when you find an extreme probability not the large one

Question 42

how do we find the critical region? what about for greater than or equal too probabilites? what about two tail tests?

Answer 42

use binomial CD table function, so you have the list of probablities, compare against the significance level. Do 1 minus for greater than or equal too Do above and below the probablity

Question 43

what is the format for sample means hypothesis testing?

Answer 43

X bar is normally distributed( mu, sigma squared over n)

Question 44

what is the difference with sample means hypothesis test? what about for critical region of sample means hypothesis testing?

Answer 44

mu is the population etc etc, use the x bar normal equation find probability with normal CD find the area of significance level then find value then compare to signif