Evaluating Data Purpose of Experiments Evaluating Experiments Is to test theory? Let’s do it!!!
Evaluating Data
description
Transcript of Evaluating Data
Evaluating DataEvaluating Data
Is my data reliable?Is my data reliable?
Mrs Sharpe likes a nice piece of cod Mrs Sharpe likes a nice piece of cod from the fish shop.from the fish shop.
Two fishmongers ‘Fish R Us’ and Two fishmongers ‘Fish R Us’ and ‘Something Fishy’ have signs outside. ‘Something Fishy’ have signs outside. They both say; They both say;
Cod average length 30cm £2.50Cod average length 30cm £2.50 Mrs Sharpe buys one cod fillet each Mrs Sharpe buys one cod fillet each
week and measures them.week and measures them.
Fish R UsFish R Us
•Length of cod fillet in cm
Week 1: 29cm Week 2: 30cm Week 3: 31cm Average length 30cm
•Is the advert for cod fillets 30cm true?
•How reliable are Fish R Us? Are the fish all about 30cm long?
Yes the average length of a cod fillet is 30cm
Quite reliable the average is 30cm and the spread is only 1cm.
1 in 30 is quite small.
Something FishySomething Fishy
•Length of cod fillet in cm
Week 1: 30cm Week 2: 20cm Week 3: 40cm Average length 30cm
•Is the advert for cod fillets 30cm true?
•How reliable are Something Fishy? Are the fish all about 30cm long?
Yes the average length of a cod fillet is 30cm
Not very reliable the average is 30cm but the spread is 10cm.
10 in 30 is a lot.
For Example:For Example:
Three pieces of data readThree pieces of data read5050 5252 4848
Work out the average and the spread.
How reliable do you think the data is?
Average =50 Spread = 2Average =50 Spread = 2
The data is fairly reliable as 2 in 50 is quite The data is fairly reliable as 2 in 50 is quite small.small.
Another example:Another example:
Three pieces of data readThree pieces of data read100100 105105 9595
Work out the average and the spread.
How reliable do you think the data is?
Average =100 Spread = 5Average =100 Spread = 5
The data is fairly reliable as 5 in 100 is The data is fairly reliable as 5 in 100 is quite small.quite small.
Another example:Another example:
Three pieces of data readThree pieces of data read8585 4040 8585
Work out the average and the spread.
How reliable do you think the data is?
Average =70 Spread = 22.5Average =70 Spread = 22.5
The data is unreliable as 22.5 in 70 is a The data is unreliable as 22.5 in 70 is a lot.lot.