Unit 3: Sampling techniques and descriptive statistics - Practice Quiz

1 In statistics, a sample is best defined as:

2 The complete set of all items or individuals under study is called the:

3 One main advantage of sampling over studying the whole population is that it:

4 In simple random sampling, every member of the population has:

5 Which of the following is an example of non-random sampling?

6 Dividing a population into subgroups and then randomly selecting from each is called:

7 In which sampling method does the researcher select units based on personal expertise or judgment?

8 Data that describes qualities or categories, such as colour or gender, is called:

9 Which of the following is an example of quantitative data?

10 Data that can be ranked in a meaningful order, such as poor, average, good, is called:

11 The arithmetic mean of the values is:

12 The median of a data set is the:

13 The median of the values is:

14 The arithmetic mean is calculated by:

15 Which measure of central tendency is most affected by extreme values (outliers)?

16 Which of the following is a characteristic of an ideal average?

17 An ideal average should be based on:

18 The value of Karl Pearson's coefficient of correlation always lies between:

19 A Karl Pearson correlation coefficient of indicates:

20 Inferential statistics is mainly used to:

21 A researcher studies employees but collects data from only of them. The employees represent the:

22 Which of the following is the main advantage of sampling over a complete census?

23 A researcher selects every person from a list of customers to form a sample. This method is called:

24 A market researcher interviews shoppers who happen to be near the store entrance because they are easy to reach. This is an example of:

25 To ensure each subgroup (age group) is proportionally represented, a researcher divides the population into age groups and samples from each. This is:

26 Which of the following is a key feature that distinguishes random sampling from non-random sampling?

27 The variable "customer satisfaction" measured as Poor, Average, Good, Excellent is an example of which type of data?

28 Which of the following variables is quantitative (numerical)?

29 A dataset records the gender of respondents as Male or Female. This is best classified as:

30 The arithmetic mean of the values is:

31 Find the median of the data set: .

32 In a dataset containing an extreme outlier, which measure of central tendency is most appropriate?

33 The mean of observations is . If one observation of value is removed, the mean of the remaining becomes:

34 The median of the ordered data is:

35 Which of the following is NOT a desirable characteristic of an ideal average?

36 Which characteristic of the arithmetic mean makes it suitable for further algebraic and statistical treatment?

37 Karl Pearson's coefficient of correlation always lies within which range?

38 If the correlation coefficient between two variables is , this indicates:

39 Karl Pearson's coefficient of correlation is given by which formula?

40 A value of between two variables indicates:

41 For a bivariate dataset, the covariance is , the standard deviation of is , and the standard deviation of is . What is the Karl Pearson coefficient of correlation?

42 If each value of is multiplied by and each value of is increased by , how does the Karl Pearson correlation coefficient change?

43 A dataset of observations has a mean of . On rechecking, it is found that an observation recorded as should have been . What is the corrected mean?

44 Which characteristic of an ideal average is primarily violated by the mode when a dataset has two peaks of equal frequency?

45 A researcher divides a population into strata by age group and then randomly selects proportionally from each stratum. Later the same list is sampled by selecting every -th person. Which two techniques are being combined?

46 The mean of items was . Two items and were wrongly read as and . What is the correct mean?

47 Two variables have a Karl Pearson correlation coefficient of . What proportion of the variation in one variable is linearly explained by the other?

48 A survey records customer satisfaction as 'Poor', 'Average', 'Good', 'Excellent'. Which statement is most accurate about this data?

49 For a moderately skewed distribution, the mode is and the mean is . Using the empirical relationship, what is the approximate median?

50 Which of the following best describes the concept of 'sampling error'?

51 The regression coefficients of a dataset are and . What is the value of the correlation coefficient?

52 A journalist interviews people found by asking initial respondents to refer their acquaintances, useful for studying a hidden population of undocumented workers. This technique is:

53 The combined mean of two groups is . Group A has items with mean , and Group B has items with mean . What is the value of ?

54 In hypothesis testing, a Type I error occurs when:

55 Which average satisfies the maximum number of characteristics of an ideal average, being rigidly defined, based on all observations, and capable of further algebraic treatment?

56 A student computes for a dataset. What is the most appropriate conclusion?

57 Which of the following variables is best classified as discrete quantitative data?

58 In a distribution of incomes with a few extremely high earners, which measure of central tendency is most appropriate and why?

59 A researcher wants to generalize findings from a sample to a population using probability theory. This process best exemplifies:

60 A factory quality inspector, needing quick results, tests only the units placed nearest to the office door each morning. What is the key limitation of this approach?