Sampling Things to remember: Random sampling is where every member of the population has an equal chance of being chosen, which makes it fair. With systematic sampling you are unlikely to get a biased sample. Stratified sampling is the best way to reflect the population accurately. Stratified sample = Questions: 1. In Holborn School there are 460 students in Key Stage 3 320 students in Key Stage 4 165 students in Key Stage 5 is carrying out a survey. He needs a sample of 100 students stratified by Key Stage. Work out the number of students from Key 3 there should be in the sample. ........................................................... for Question is 2 marks) 2. Henri is carrying out a survey of the people aged 65 and over in his village. The table shows information about these people. Henri is going to take a sample of 30 people stratified by age. How many people aged 75 79 should be in the sample? – ........................................................... (Total for Question is 3 marks) 3. The table shows information about 1065 students. Elena takes a stratified sample of 120 students by year group and by gender. Work out the number of Year 8 female students in her sample. ........................................................... (Total for Question is 2 marks)
Sampling Things to remember: Random sampling is where every member of the population has an equal chance of being chosen, which makes it fair. With systematic sampling you are unlikely to get a biased sample. Stratified sampling is the best way to reflect the population accurately. Stratified sample = Questions: 1. In Holborn School there are 460 students in Key Stage 3 320 students in Key Stage 4 165 students in Key Stage 5 is carrying out a survey. He needs a sample of 100 students stratified by Key Stage. Work out the number of students from Key 3 there should be in the sample. ........................................................... for Question is 2 marks) 2. Henri is carrying out a survey of the people aged 65 and over in his village. The table shows information about these people. Henri is going to take a sample of 30 people stratified by age. How many people aged 75 – 79 should be in the sample? ........................................................... (Total for Question is 3 marks) 3. The table shows information about 1065 students. Elena takes a stratified sample of 120 students by year group and by gender. Work out the number of Year 8 female students in her sample. ........................................................... (Total for Question is 2 marks)
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