Question 1

Which of the following is TRUE about the use of histograms in data presentation?

Accepted Answer

Histograms are used for continuous data and display frequencies with contiguous bars.

Question 2

A researcher collects the following data on the number of visits to a clinic: 1, 3, 5, 2, 4, 3, 1, 4, 3, 2, 3, 4, 2, 2, 3. What is the mode of this dataset?

Accepted Answer

3

Question 3

Which measure of central tendency is LEAST affected by extreme values (outliers) in a dataset?

Accepted Answer

Median

Question 4

Given the following data set: 73, 77, 84, 87, 89, 91, 94. What is the range?

Accepted Answer

$$94 - 73 = 21$$

Question 5

Which of the following best describes a positively skewed distribution?

Accepted Answer

A distribution with a tail towards positive values (right-skewed)

Question 6

A frequency distribution table for birth weights (kg) has the following class interval: 2.0–2.4. What is the lower class boundary for this interval?

Accepted Answer

$$1.95$$

Question 7

Which graphical method allows you to recover individual data values from the plot?

Accepted Answer

Stem-and-leaf plot

Question 8

A dataset has the following values: 7, 8, 12, 15, 10, 9, 8, 131. Calculate the mean.

Accepted Answer

$$\frac{200}{8} = 25$$

Question 9

Which of the following is NOT an advantage of using the mean as a measure of central tendency?

Accepted Answer

It is not affected by extreme values.

Question 10

For a dataset with an even number of values, how is the median calculated?

Accepted Answer

The average of the two middle values in the ordered dataset.

Question 11

A bar chart is used to present which type of data?

Accepted Answer

Categorical data with separated bars

Question 12

Which formula is used to calculate the sample standard deviation $$s$$?

Accepted Answer

$$s = \sqrt{\frac{\sum (x - \bar{x})^2$}{n-1}}$$

Question 13

In a symmetric distribution, approximately what percentage of data lies within two standard deviations of the mean?

Accepted Answer

95%

Question 14

Which measure of variability is most appropriate for describing the spread of a skewed dataset?

Accepted Answer

Percentile (e.g., interquartile range)

Question 15

A pie chart is most suitable for which type of data?

Accepted Answer

Nominal (categorical) data

Question 16

If a dataset is bimodal, which statement is correct?

Accepted Answer

There are two values that occur most frequently.

Question 17

Which of the following is a disadvantage of using the mode as a measure of central tendency?

Accepted Answer

It may end up with more than one value (bi/tri-modal).

Question 18

A researcher is analyzing cholesterol values (in mmol/L) for 16 patients. The 25th percentile (Q1) is 3.85 mmol/L and the 75th percentile (Q3) is 5.45 mmol/L. What is the interquartile range?

Accepted Answer

$$5.45 - 3.85 = 1.6$$ mmol/L

Question 19

Which of the following statements is TRUE regarding the use of mean and standard deviation versus median and percentiles?

Accepted Answer

Mean and standard deviation are best for symmetric data; median and percentiles are best for skewed data.

Data Presentation and Descriptive Statistics: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard