sampling

. Which of the following is a simple random sample?

(i) A numbered list is made of all the students in year 10 and every 10th student is selected.

(ii) A numbered list is made of all the students in year 10 and a random number generator is used to select students

• (a) (i) only

• (b) (ii) only

• (c) both (i) and (ii)

• (d) neither (i) nor (ii)

2. Gita wants to survey student opinions about the school uniform policy in her school. She selects 20 girls and 20 boys at random from a list of all the students in her school. What type of sampling has Gita used?

• Cluster sampling

• (b) Stratified sampling

• (c) simple random sampling

• (d) Self-selected sampling

3. Jamie wants to collect data about whether Facebook users use other types of social media as well. He posts a survey on his Facebook page and asks for responses. What type of sampling has Jamie used?

• a) Cluster sampling

• (b) Stratified sampling

• (c) Quota sampling

• (d) Self-selected sampling

4. Jamie wants to collect data about whether Facebook users use other types of social media as well. He posts a survey on his Facebook page and asks for responses.

Gita wants to survey student opinions about the school uniform policy in her school. She selects 20 girls and 20 boys at random from a list of all the students in her school.

Which one of the following statements is true?

• (a) Gita’s sample and Jamie’s sample are both likely to be biased

• (b) Gita’s sample is likely to be biased but Jamie’s is not

• (c) Jamie’s sample is likely to be biased but Gita’s is no

• (d) Neither Gita’s sample nor Jamie’s sample are likely to be biased

5. Molly wants to collect data about the lengths of words in books for young children. She selects three books from her 4 year-old brother’s collection and for each book she writes down the third word in every sentence. What type of sampling has Molly used?

• (a) Opportunity sampling

• (b) Cluster sampling

• (c) Stratified sampling

• (d) Quota sampling

6. Pedro wants to collect data about voting intentions in his local constituency. Which of the following methods would give Pedro a simple random sample?

• (a) select at random from the telephone directory

• (b) select at random from the electoral register

• (c) select at random from a complete list of addresses

7. A telephone company wants to get feedback about their service from customers who have their landline and broadband package. Which of the following methods would give a representative sample?

• (a) Telephoning a randomly chosen set of customers between 10 am and 12 noon on a weekday

• (b) Telephoning a randomly chosen set of customers between 7 pm and 9 pm on a weekday

• (c) Sending an email to a randomly chosen set of customers asking them to respond to an online survey

• (d) None of the above

Find the median and interquartile range of each of the set s of data below. (i) 2 5 3 8 1 7 2 4 6 8 4

• Median 7 IQR 3

• Median 5 IQR 4

• Median 4 IQR 5

• Median 4 IQR 3

The data below shows the weights of 15 babies born on the same day in a particular hospital.

3.61 4.85 3.47 2.53 3.07 3.39 1.36 3.84 4.21 3.73 2.84 3.22 4.15 5.81 4.79

(i) Find the mean and standard deviation of the weights of this group of babies

• mean 3.65 SD 1.03

• mean 3.65 SD 1.3

• mean 3.12 SD 1.03

• mean 3.04 SD 1.13