maths and stats

Question 1

circumference of a circle

Answer 1

2 x pi x r

Question 2

area of a circle

Answer 2

pi x r2

Question 3

sa of a cuboid

Answer 3

2(bh+bl+hl)

Question 4

volume of a cuboid

Answer 4

hxbxl

Question 5

volume of a cube

Answer 5

bxhxw

Question 6

sa of a cube

Answer 6

6x a2

Question 7

why do we do stats tests

Answer 7

to see if the results are reliable, eliminating chance to identify if the results were statistically significant

Question 8

why would you use a t test

Answer 8

there are taken measurements
you want to compare the means of two sets of the same type of data to see if there is a statistical difference or if the differences are due to chance

Question 9

t tests can only be carried out if the data is

Answer 9

continuous and normally distributed

Question 10

what is a null hypothesis

Answer 10

there is no significant difference between the means

Question 11

what is an alternative hypothesis

Answer 11

there is a significant difference between the means

Question 12

difference between data for a paired and unpaired t test

Answer 12

comparing means of two sets of data collected from the same individual= paired

comparing means of 2 categorical groups of individuals=unpaired

Question 13

how do you calculate the degrees of freedom for an unpaired t test

Answer 13

n1+n2-2 (where n is the number of values in each data set)

Question 14

what does the dof indicate for an unpaired t test

Answer 14

the sum of the number of data points in each data set minus the number of data sets

Question 15

how do you calculate the degrees of freedom for a paired t test

Answer 15

n-1 (where n is the number of pairs of data)

Question 16

step 1 of t test: state…

Answer 16

state a null hypothesis

eg there is no significant difference between the length of holly at 0.5 m and 1.0m

Question 17

look in the table to see how..

Answer 17

many decimal places to give in your answer but if not just give to 3

Question 18

after carrying out the test/using the formula provided what should you do next (t test)

Answer 18

find the critical value at p=0.5

Question 19

what is the template for a t test conclusion

Answer 19

the stidents t test value i of …. if greater than the critical value of …… so we can reject the null hypothesis. there is a significant difference between eg the lengths of holly leaves at 0.5 m and 1.0m

Question 20

standard deviation is NOT

Answer 20

a statistical test

Question 21

what does sd tell you

Answer 21

how much the values in a single data sample vary

Question 22

what does a low sd indicate

Answer 22

the data points are closely grpuped to the mean=greater precision=greater repeatability=smaller the error bar

A GOOD THING

Question 23

what does a high sd indicate

Answer 23

less precision, not repeatable results

Question 24

process for calculating sd on my calculator

Answer 24

home
stats
1-variable
input all the x values
press =
1-var results
down once to sx

Question 25

how to draw error bars

Answer 25

the sd above and below the mean

Question 26

is it good that the error bars do not overlp and what does this mean

Answer 26

yes because it suggests that the difference between these means is significant

Question 27

once a significant difference has been idenifed what can be done next

Answer 27

a stats test can be done eg t test to show how significant the differences are

Question 28

the bigger the error bar.....

Answer 28

the greater the spread of the data is about the mean-results are not very precise > the data is unreliable

Question 29

the smaller the error bar....

Answer 29

less deviation from the mean/less spread therefore more precise > data is more reliable