Lecture 1 mcqs

Question 1

1. A researcher records the temperature (in °C) of a chemical solution every 5 minutes. What type of variable is temperature in this case?
   A) Nominal
   B) Ordinal
   C) Continuous
   D) Discrete

Answer 1

C

Question 2

2. In a survey, participants are asked to choose their blood group (A, B, AB, O). Which type of variable is this?
   A) Ordinal
   B) Continuous
   C) Binary
   D) Nominal

Answer 2

D

Question 3

3. A study measures number of hospital admissions per patient over 1 year. Which type of data is this?
   A) Continuous
   B) Nominal
   C) Discrete
   D) Ordinal

Answer 3

C

Question 4

4. A questionnaire asks participants to rate pain as “none”, “mild”, “moderate”, or “severe”. This is an example of:
   A) Nominal
   B) Ordinal
   C) Binary
   D) Continuous

Answer 4

B

Question 5

5. Which of the following best represents a binary variable?
   A) Systolic blood pressure
   B) Marital status
   C) Gender (Male/Female)
   D) Ethnicity

Answer 5

C

Question 6

6. Which plot is most appropriate for visualizing the distribution of cholesterol levels in a population?
   A) Bar chart
   B) Histogram
   C) Pie chart
   D) Dot plot

Answer 6

B

Question 7

. A histogram shows a distribution where most values are low, with a long tail to the right. What is the shape?
A) Symmetric
B) Bell-shaped
C) Left-skewed
D) Right-skewed

Answer 7

D

Question 8

8. In a boxplot, the line inside the box represents:
   A) Mean
   B) Mode
   C) Median
   D) Standard deviation

Answer 8

C

Question 9

9. Which feature is used to identify outliers in a box-and-whisker plot?
   A) Points beyond Q1 and Q3
   B) Points outside 1.5 × IQR from Q1 or Q3
   C) Points above the median
   D) Points below the range

Answer 9

B

Question 10

10. You are comparing three box plots. One has a median close to Q1, a long upper whisker, and no outliers. This distribution is likely:
    A) Left-skewed
    B) Right-skewed
    C) Symmetric
    D) Uniform

Answer 10

B

Question 11

11. A dataset contains the values: 2, 2, 3, 5, 50. Which measure of central tendency is least appropriate to describe this data?
    A) Median
    B) Mode
    C) Mean
    D) Range

Answer 11

C

Question 12

12. Which measure is most resistant to extreme values (outliers)?
    A) Mean
    B) Median
    C) Range
    D) Standard deviation

Answer 12

B

Question 13

13. What happens to the mean and standard deviation when you add a large outlier to a data set?
    A) Both increase
    B) Mean increases, SD decreases
    C) Mean unchanged, SD increases
    D) Only median changes

Answer 13

A

Question 14

14. Which measure tells you the average distance of data points from the mean?
    A) Range
    B) Interquartile Range
    C) Standard Deviation
    D) Mode

Answer 14

C

Question 15

5. If the range of a bell-shaped distribution is 60, what is a rough estimate of its standard deviation?
   A) 10
   B) 12
   C) 6
   D) 15

Answer 15

Answer: A (Since SD ≈ range / 6)

Question 16

6. You receive a dataset with multiple variables. What is the first thing you should do?
   A) Run a t-test
   B) Calculate the mean
   C) Plot and explore the data visually
   D) Perform regression

Answer 16

C

Question 17

17. If your histogram shows a symmetric shape, which relationship is likely true?
    A) Mean = Median
    B) Mean > Median
    C) Median > Mean
    D) Mean < Median

Answer 17

A

Question 18

18. Which of the following is NOT a measure of variation?
    A) Variance
    B) Standard deviation
    C) Interquartile range
    D) Mode

Answer 18

D

Question 19

19. Which is most affected by extreme outliers in a dataset?
    A) Median
    B) Interquartile range
    C) Mean
    D) Mode

Answer 19

C

Question 20

20. A researcher finds that the mean test score is higher than the median. What can you infer about the distribution?
    A) It is left-skewed
    B) It is symmetric
    C) It is right-skewed
    D) It is uniform

Answer 20

C

Question 21

21. A researcher finds the mode of test scores is 90, while the mean is 75 and the median is 78. This distribution is most likely:
    A) Symmetric
    B) Right-skewed
    C) Left-skewed
    D) Uniform

Answer 21

C

Question 22

22. Which of the following statements about the median is TRUE?
    A) It is the arithmetic average
    B) It is sensitive to outliers
    C) It divides the data into 3 quartiles
    D) It is the middle value when data are ordered

Answer 22

D

Question 23

23. Which graphic is best to compare frequency of different blood types in a population?
    A) Histogram
    B) Bar chart
    C) Boxplot
    D) Scatterplot

Answer 23

B

Question 24

24. In a bell-shaped distribution, approximately what percentage of data falls within 1 standard deviation of the mean?
    A) 50%
    B) 68%
    C) 75%
    D) 95%

Answer 24

B

Question 25

25. The primary purpose of calculating variance is to: A) Identify outliers B) Describe central tendency C) Measure spread of data D) Calculate correlation

Answer 25

C

Question 26

26. A study collects responses to the question “Which sport do you play?” What type of data is collected? A) Ordinal B) Nominal C) Discrete D) Continuous

Answer 26

B

Question 27

27. Which of the following would be best to summarise central tendency in highly skewed data? A) Mean B) Standard deviation C) Median D) Mode

Answer 27

C

Question 28

28. A researcher wants to summarise the variation in age among patients. Which would be LEAST useful? A) Interquartile range B) Range C) Standard deviation D) Mode

Answer 28

D

Question 29

29. If a dataset has no repeated values, what is true about its mode? A) Equal to the median B) Zero C) Not defined D) Same as the mean

Answer 29

C

Question 30

30. Which of the following is most useful for identifying skewness in a distribution? A) Mean alone B) Boxplot C) Scatter plot D) Pie chart

Answer 30

B

Question 31

31. A boxplot shows a long lower whisker and median closer to Q3. What is the likely shape? A) Uniform B) Symmetric C) Left-skewed D) Right-skewed

Answer 31

C

Question 32

32. Which of the following is TRUE about histograms and bar charts? A) Both are used for categorical data B) Histogram bars do not touch; bar chart bars do C) Bar charts are for continuous data D) Histograms display distribution of continuous variables

Answer 32

D

Question 33

33. What best describes the coefficient of variation? A) Range divided by standard deviation B) Standard deviation divided by mean C) Mean divided by sample size D) Mode minus median

Answer 33

B

Question 34

34. A researcher finds the mean heart rate of patients is 72 bpm with a SD of 12 bpm. A patient with 120 bpm would be considered: A) Normal B) A mode C) An outlier D) The median

Answer 34

C

Question 35

35. What visualisation would best compare pulse rate distributions between males and females? A) Box plots B) Pie chart C) Dot plot D) Stem-and-leaf plot

Answer 35

A

Question 36

36. Which of these is not a valid summary measure for numerical data? A) Mean B) Median C) Bar chart D) Standard deviation

Answer 36

C

Question 37

37. Which best represents the typical “value” in a dataset? A) Standard deviation B) Mean C) Range D) Quartile

Answer 37

B

Question 38

38. Which of the following visualisations would be most helpful to detect outliers? A) Bar chart B) Histogram C) Boxplot D) Line graph

Answer 38

C

Question 39

39. A dataset has mean = median = mode. This distribution is likely: A) Left-skewed B) Right-skewed C) Uniform D) Symmetric

Answer 39

D

Question 40

40. Which summary statistic changes the most if a very large value is added to a small data set? A) Mode B) Median C) Mean D) Interquartile range

Answer 40

C

Question 41

41. A dataset of exam scores has a mean of 70 and a standard deviation of 5. A student scores 85. What does this indicate? A) They are one SD above the mean B) They are three SDs below the mean C) They are three SDs above the mean D) They are at the median

Answer 41

C

Question 42

2. Which is TRUE regarding the interquartile range (IQR)? A) It includes the maximum and minimum values B) It measures the spread of the middle 50% of data C) It equals the mean minus the median D) It is always greater than the standard deviation

Answer 42

B

Question 43

3. Which of these statements about the mean is FALSE? A) It considers all data values B) It is affected by outliers C) It is always equal to the median D) It is used in calculating standard deviation

Answer 43

C

Question 44

44. The most appropriate summary measure for a highly skewed income distribution is: A) Mean B) Median C) Mode D) Range

Answer 44

B

Question 45

45. What happens to the standard deviation if every data value is multiplied by 3? A) Stays the same B) Becomes 1/3 of the original C) Multiplied by 3 D) Multiplied by 9

Answer 45

C

Question 46

46. A histogram is constructed for students’ study hours. Most students study 1–2 hours, with a long tail up to 12 hours. This is: A) Symmetric B) Bell-shaped C) Left-skewed D) Right-skewed

Answer 46

D

Question 47

7. What is the range for this dataset: {12, 18, 23, 34, 47}? A) 23 B) 12 C) 35 D) 34

Answer 47

D

Question 48

48. You’re exploring a dataset and see that one data point lies far beyond the rest. What should you check first? A) If it is the mean B) If it’s an outlier or error C) Whether it matches the mode D) Whether it’s a nominal value

Answer 48

B

Question 49

49. Which of these best describes a symmetric distribution? A) Mean < median B) Mean > median C) Median = mode = mean D) More data lie on one side

Answer 49

C

Question 50

50. You have the ages of participants: 19, 22, 24, 27, 28, 29, 32, 35. What is the median? A) 27 B) 26 C) 28 D) 25.5

Answer 50

Answer: B (Median = (24+27)/2 = 25.5)

Question 51

51. A student presents a pie chart of different eye colours. This is a correct chart for which type of data? A) Continuous B) Ordinal C) Nominal D) Discrete

Answer 51

C

Question 52

52. Which of the following variables would most likely produce a symmetric bell-shaped histogram? A) Height of adults B) Favourite movie genre C) Number of children in families D) Eye colour

Answer 52

A

Question 53

53. Which measure would remain unchanged if a constant was added to every value in the data set? A) Mean B) Median C) Standard deviation D) Range

Answer 53

C

Question 54

54. What effect does a single extreme high value have on the mean? A) No effect B) It pulls the mean lower C) It pulls the mean higher D) It removes the mean

Answer 54

C

Question 55

55. If a dataset's mean = 20 and SD = 4, what approximate range covers most values assuming normal distribution? A) 12 to 28 B) 8 to 32 C) 16 to 24 D) 18 to 22

Answer 55

Answer: A (±2 SD = 20 ± 8 = 12–28)

Question 56

56. A boxplot of recovery times shows a median of 7 days, with a lower whisker of 2 and an upper whisker of 30. What can you infer? A) Data is symmetric B) Right-skewed with a potential outlier C) Left-skewed with a high mode D) Mean is equal to median

Answer 56

B

Question 57

7. When might it be inappropriate to use the standard deviation? A) For categorical data B) For large data sets C) When data is normally distributed D) When mean and median are equal

Answer 57

A

Question 58

58. Which is not a measure of central tendency? A) Mean B) Median C) Mode D) Interquartile Range

Answer 58

D

Question 59

59. Which of these would best help you compare distributions of a continuous variable between two groups? A) Pie chart B) Boxplot C) Bar chart D) Line graph

Answer 59

B

Question 60

60. When comparing two skewed datasets, which measure would be most meaningful? A) Mean B) Mode C) Median D) Range

Answer 60

C