Answer keys for Assignment 10: Measurement of study variables (The correct answer is underlined in bold text)

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1 Answer keys for Assignment 10: Measurement of study variables (The correct answer is underlined in bold text) 1. A quick and easy indicator of dispersion is a. Arithmetic mean b. Variance c. Standard deviation d. Range 2. Choose the odd one among the following a. Range b. Variance c. Mode d. Standard deviation 3. In a study, participants are asked to indicate the type of pet they have at home (ex: dog, cat) from a given list. This type of variable is classified as a. Ordinal b. Nominal c. Continuous d. Discrete 4. Most commonly used measure of central tendency is a. Mode b. Median c. Mean d. Range 5. All are measures of dispersion except a. Arithmetic mean b. Variance c. Standard deviation d. Range 6. In a study on hypertension (High blood pressure), patients are categorised based on their systolic blood pressure (SBP) as pre-hypertension, hypertension stage-i and hypertension stage-ii. What type of variable is this? a. Qualitative b. Descriptive c. Nominal d. Ordinal

2 7. Number of children per household is an example of a continuous variable a. True b. False 8. In a study, researchers are interested in measuring the cholesterol levels of participants. Cholesterol level is a variable a. Ordinal b. Nominal c. Continuous d. Discrete 9. In the following set of data, what is the mean? 4,1,9,7,3,8,2,6 a. 5 b. 40 c. 10 d First quartile (Q1) is equivalent to percentile a. 25 th b. 50 th c. 75 th d. 100 th

3 Answer keys for Assignment 11: Sampling methods (The correct answer is underlined in bold text) 1. The following statement is correct regarding sampling error a. Sampling error is difficult to measure in simple random sampling b. Sampling error is easy to measure in stratified sampling c. The magnitude of error can be measured in non-probability samples d. The magnitude of error can be measured in probability samples 2. Random sampling in probability samples reduces the possibility of selection bias a. True b. False 3. All the following statements are true regarding simple random sampling except a. Sampling error is easily measurable b. It needs a complete list of all units c. It ensures equal chance of selection for each unit d. It always achieves best representativeness 4. The sampling technique in which every unit in the population has a known probability of being selected in a sample a. Convenience sampling b. Probability sampling c. Purposive sampling d. Subjective sampling 5. Based on the degree of use of mobile phones, a researcher divides the population into three groups (low, moderate, high use). If the researcher then draws a random sample from each user group independently, he has created a sample a. Systematic random b. Simple random c. Stratified random d. Group data 6. The sampling method that allows drawing valid conclusion about the population a. Non-probability sampling b. Convenience sampling c. Probability sampling d. Subjective sampling

4 7. Sampling based upon equal chance of selection is called a. Stratified random sampling b. Simple random sampling c. Systematic sampling d. Subjective sampling 8. A researcher wishing to draw a sample from sequentially numbered houses uses a random starting point and then selects every 7 th house, s/he has thus drawn a sample a. Sequential b. Systematic random c. Simple random d. Stratified random 9. Methods used in probability samples are a. Stratified sampling b. Multi-stage sampling c. Cluster sampling d. All of the above 10. People who volunteer or who can be easily recruited are used in a sampling method called a. Cluster sampling b. Multi-stage sampling c. Convenience sampling d. Systematic sampling

5 Answer keys for Assignment 12: Calculating sample size and power (The correct answer is underlined in bold text) 1. The following steps are part of sample size estimation except a. Identify major study variable b. Decide on the desired precision of the estimate c. Adjust for population size d. Adjust for selection bias 2. Population variance can be estimated from a. A pilot study b. Reports of previous studies c. a & b d. Population variance can t be estimated 3. The recommended minimum level of power is a. 5% b. 95% c. 80% d. 25% 4. Statistical power is defined as the probability of a. Accepting a null hypothesis when it is false b. Rejecting a null hypothesis when it is true c. Rejecting a null hypothesis when it is false d. Failing to reject a null hypothesis when it is false 5. The power of a study a. Does not influence the sample size b. Represented as α c. 1-β d. All of the above statements are true 6. When estimating sample size for a study, we need to adjust for a. Expected response rate b. Estimated design effect c. Population size d. All the above

6 7. Sampling error is a function of a. Sample size b. Variability in measurement c. a and b d. None of the above 8. Steps in the estimation of sample size include all of the following except a. Identify major study variable b. Decide on the desired precision of the estimate c. Adjust for population size d. Adjust for selection bias 9. Design effect of more than 1 needs to be considered in studies involving a. Cluster sampling b. Simple random sampling c. Stratified random sampling d. Non-probability sampling α is the probability associated with a. Type-I error b. Type-II error c. Level of significance d. Level of confidence