maths Qs

Question 1

P value is > 0.5. state what this P value tells you about this difference. Explain your answer using the words probability and chance.

Answer 1

This difference is not significant. There is a greater than a 0.5 probability that this difference is due to chance

Question 2

A teacher studying these data with her students told her lass that no definite conclusions could be drawn when comparing the mean values in the graph. Suggest why the teacher said this

Answer 2

no error bar/ SD

to show if overlap occurs so difference in means is not significant/ due to chance

Question 3

if overalap in SD

Answer 3

indicated no significant differencnce

Question 4

if no overlap in SDs

Answer 4

significant difference

Question 5

24hours to min

Answer 5

24 × 60 = 1440 minutes

Question 6

nm to micrometers

Answer 6

1000 nm = 1 micrometer

Question 7

cm to micrometers

Answer 7

1cm = 10000 micrometer

Question 8

suggest and explain

Answer 8

point and why important

Question 9

Suggest and explain two ways in which the scientists could have improved the
method used for data collection in this investigation.

Answer 9

1. Collect at more times of the year so more points on graph/better line (of best fit) on graph;
2. Counted number of individuals in each species so that they could calculate index of diversity;
3. Collected from more sites/more years to increase accuracy of (mean) data;

Question 10

The scientists also concluded that this heat treatment did not affect the xylem.
Explain how the results in Table 4 support this conclusion

Answer 10

1. (The water content of the leaves was) not different because (means ± 2) standard deviations overlap;
2. Water is (therefore) still being transported in the xylem (to the leaf)
   OR
   Movement in xylem is passive so unaffected by heat treatment;

Question 11

mm to micro meters

Answer 11

x1000

Question 12

if graph going down

Answer 12

negative correlation

Question 13

Evaluate Qs ideas

Answer 13

1- postive or negative correlation - does it match the statement

2- original data not know

3- another factor causing changes- e.g. diet

4- little evidence/ data for higher values

5- large SD difference - less precise - greater uncertainly

6- No statical test done to show if difference are signficant

Question 14

Answer 14

Advantage:
1. Over longer period so more representative

2- Diet may vary during the year/from day to day

Disadvantage:
2. Relies on long term memory so may not be accurate

3- Recall of 24 hr diet likely to be more accurate

Question 15

Answer 15

chi squared

Question 16

The scientists calculated a P value of 0.03 when testing their null hypothesis.
What can you conclude from this result? Explain your answer.

Answer 16

1. Probability that difference is due to chance is less than 0.05
2. REJECT null hypothesis;
3. Presence of KIR2DS1/allele DOES significantly affect the frequency of high birth mass;

Question 17

dilution

Answer 17

Question 18

Points to assess if data is reliable

Answer 18

1- Large sample size

2- Individuals chosen at random

3- Equal number of males and females / same sex

4- Repeat readings

5- Individuals healthy

Question 19

Points to challenge assumptions made with data

Answer 19

1- Influence of other factors

2- Further studies required

3- How great is the difference / data

Question 20

null hypothesis

Answer 20

has no effect

 Correlation coefficient;

Question 21

why use median

Answer 21

small sample size

outliers

Question 22

why used a control

Answer 22

1- Used to compare effect of other treatments / as a baseline;

2.      Shows / Measures effect of substance (X);