GRAPH PRACTICE: IDENTIFYING TRENDS IN DATAQ1: LOOKING AT ANOMALIES

An anomaly is a piece of data that doesn’t fit in with the rest of the data.

A scientist measured the change in mass pf potatoes submerged in dofferent concentrations of sucrose solution, and tabulated the results below.

Concentration of sucrose (M)

Change in mass of piece of potato (g)Group A’s

measurementsGroup B’s

measurementsa) Average mass

change ( A + B )/2

0.25 0.02 0.030.5 0.05 0.051 0.12 2.3

1.5 0.17 0.142 0.21 0.2

b) Complete the table by working out the average. mass change for each concentration of sucrose

c) Circle the anomalous result in the table below. d) Should you include or remove the anomalous data from your analysis?? Why?

____________________________________________________________________________________________________________________________________________________________________________

e) Plot the average change in mass of a piece of potato in the graph using two different colours – one where the anomalous data has been included, and one where it has been deleted.

1

Q2: DESCRIBING TRENDSa) A scientist investigated the effect of adding different quantities of amylase enzyme to

carbohydrate, and measuring the time taken for the carbohydrate to be digested.

Volume of amylase enzyme mixed with 10ml of carbohydrate solution (in ml)

Time taken for the digestion of all the carbohydrate (minutes)

2 344 296 258 20

10 1212 5

2

b) Make a line graph of the data.c) Describe the trend in the graph:

____________________________________________________________________________________________________________________________________________________________________________

3

Q3 The table below was produced by a student who investigated whether temperature increased the rate of diffusion. Estimate the missing two values.

X axis Y axisTemperature of water (oC) Time taken to fully diffuse (seconds)

20 4303040 36250 3146070 21880 140

Plot these results on a line graph below. You will have to draw the x and y axis, and come up with your own appropriate scale.

Extension: Explain why using an average value from several repeats of the same experiment would be more likely to give a value that can be reproduced by others.__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

4

4.

Fully describe the trend shown in the graph

_________________________________________________________________

_________________________________________________________________

Plot a graph of the student’s results on the grid below.

Label the x axis and draw a line of best fit.

5

Time in minutes Volume of carbon dioxide collected in

cm3

0 0

1 46

2 70

3 85

4 94

5 96

6 96

7 96

5.

Number of blades

What conclusion can be made from the results in the scatter graph?

_________________________________________________________________

_________________________________________________________________

_________________________________________________________________

_____________________________

What was the independent variable in the investigation?

________________________________________________________

What was the dependant variable in the investigation?

________________________________________________________

State one control variable for the investigation

________________________________________________________

Explain the advantage of taking repeat readings

6

Plot the results in the table on the graph below.

Draw an appropriate line of best fit

One of the points is anomalous.

Draw a ring around the anomalous point on your graph.

Predict how long it will take the liquid hydrocarbon to run through the funnel at 70 °C.

Show your working on your graph.

Time = ........................................ seconds

What conclusions can you make based on the results in the table above?

_______________________________________________________________________________________

_______________________________________________________________________________________

___________________________________________________

7

7. The chart shows deaths due to coronary heart disease in Australia

A. Describe the trend/pattern shown for males (3)B. Suggest 2 reasons why females have less CHD than males

8. The chart shows the number of male and female lung cancer cases.

Compare the trends/patterns shown by males and females. (write down as many similarities and differences) as you can).

Lung Cancer cases 2009 - 2010

Lung cancer cases

8

9: Ethylene is a chemical that causes apples to mature and ripen. The graph below shows the time it takes for apples to mature after the trees were sprayed with ethylene

5 10 15 20 25 30 35 404

6

8

10

12

14

16

Golden Apples:Gala Apples:

ethylene concentration ml/l

days

to m

atur

e

A. What is the dependent variable? B. What is the independent variableC. What is the correlation between the 2 variables?D. Compare the effects of the ethylene on the 2 apple varieties.(3)

10. The chart shows the number of Whooping cough cases and the number of people who received the vaccination between 1940 and 2009

A. What is the smallest range value shown on the x axis?B. Prior to 1975 whooping cases were decreasing but they then rose sharply.

What was the maximum number of cases recorded after 1975?C. Suggest why the number of cases increased just prior to 1980?D. Estimate to the nearest 10% the maximum vaccine uptake the government

achieved

9

11. Clostridium difficile is an antibiotic resistant bacterium. The chart below shows the number of deaths involving this bacterium in the UK over 5 years.

A. List the trends/patterns shown in this chart (4)B. Calculate the % drop in male deaths between 2007 and 2010?C. Suggest 2 reasons for the decrease in deaths due to Clostridium difficile.

10