3rd takes a long time/costly difficult to ensure whole population surveyed cannot be used if the measurement process destroys the item

Transcription

1 1a Observation or measurement of every member of a population nd 1b Two from: 1.2 3rd takes a long time/costly difficult to ensure whole population surveyed cannot be used if the measurement process destroys the item 1.2 can be hard to manage and analyse all the data. 1c The list of unique serial numbers nd 1d A circuit board nd (5 marks)

2 2a A complete collection of relevant individual people or items nd 2b Opportunity (convenience) rd Understand quota and opportunity 2c Systematic rd carry out systematic 2d Two from: not random electoral register may have errors there may not be enough (500) households on the register th 2e Either: random it avoids bias. Or: quota no frame required, continue until all quotas filled. Either: Random from people buying kitchen cleaners in a large store, as this would reduce potential bias. Or: Quota from people based on a chosen set of ages and genders who use kitchen cleaners, continuing until all quotas are filled, as this would avoid the need for a frame and allow for a more clearly representative sample th 2.4 (7 marks)

3 3a One of: to obtain a representative sample large number of students compared to staff so would be unfair to take same numbers of both th 3b A list of the names of staff and students nd 3c A member of staff or a student nd 3d Find proportions for different strata out of 60 (either explained or some sensible calculation seen) » 54 students, » 6 staff. A1 1.1b M1 3.1b 3rd carry out stratified Select at random using a random number generator. 1.1b (3)

4 3e One of: absence on the day of the survey frame may contain errors. 2.2b 5th (7 marks) 3d Must be whole numbers for A1. 4a All readers of the online newspaper nd 4b A list of readers who subscribe to the extra content nd 4c The subscribers nd

5 4d Advantage: accuracy of the data, unbiased rd Disadvantage: difficult to get a 100% response to a survey e Natural variation in a small sample rd Bias. 1.2 (7 marks)

6 5a Quota rd Understand quota and opportunity 5b Advantages two from: 2.4 5th easy to get sample size inexpensive fast can be stratified if required. 2.4 Disadvantages one from: not random could be biased c Allocate each of the males a number from 1 to b 3rd Use calculator or number generator to generate 50 different random numbers from 1 to 300 inclusive. (3) 1.1b Select males corresponding to those numbers. 1.1b carry out simple random 5d = 6 3.1b 3rd Use a random number generator to select the first name (or one of the first 6 names on the list) as a starting point and then select every 6th name thereafter to get 50 names. (3) 1.1b carry out simple random (9 marks)

7 6a There are a very large number of bags rd Bags are tested to destruction there would be no bags left b One value is less than 12 kg 2.4 3rd therefore claim is not reliable c Different samples can lead to different conclusions due to natural variations. Only a small sample taken so unreliable rd 6d Larger sample rd (7 marks)

8 7a (Quantitative) continuous st difference between qualitative and quantitative data. 7b A list of the first two digits of the date nd 7c Simple random sample 3.1b 5th using a random number generator to select five dates. 1.1b 7d Number ordered list of data. 3.1b 3rd Use random number generator is choose first selected piece of data. æ 187ö Then take every 6th value è ç 30 ø 3.1b 1.1b carry out systematic 7e Some data may be missing or erroneous. 3.2b 5th (3) (8 marks)