LECTURE 4

Question 1

What is a stem-and-leaf plot?

Answer 1

A way to display data where the “stem” represents the tens and the “leaf” represents the units

Question 2

What information can a boxplot show?

Answer 2

Median, range, interquartile range (IQR), and skewness of a dataset.

Question 3

What does the range of a dataset measure?

Answer 3

The difference between the highest and lowest values.

Question 4

What is the interquartile range (IQR)?

Answer 4

The range of the middle 50% of a dataset, from Q1 (25th percentile) to Q3 (75th percentile).

Question 5

What is skewness in data?

Answer 5

A measure of symmetry in a distribution.

Question 6

What is positive skew?

Answer 6

When data is skewed with a long tail on the right (high values).

Question 7

What is negative skew?

Answer 7

When data is skewed with a long tail on the left (low values)

Question 8

What does kurtosis measure?

Answer 8

The “tailedness” or sharpness of the peak in a distribution.

Question 9

What is mesokurtic kurtosis?

Answer 9

A normal distribution with kurtosis = 3.

Question 10

What is leptokurtic kurtosis?

Answer 10

A distribution with a sharp peak and heavy tails (kurtosis > 3).

Question 11

What is platykurtic kurtosis?

Answer 11

A distribution with a flat peak and light tails (kurtosis < 3).

Question 12

How does skewness statistic determine normality?

Answer 12

Skewness values within -1 to 1 indicate a normal distribution.

Question 13

What is the purpose of histograms in statistics?

Answer 13

To show the frequency distribution of data.

Question 14

What is a probability distribution?

Answer 14

A smooth curve showing the likelihood of values in a dataset.

Question 15

What is a normal distribution?

Answer 15

A symmetric, bell-shaped curve centered around the mean.

Question 16

Why is normality important in statistics?

Answer 16

Many statistical tests assume data is normally distributed for accurate results.

Question 17

What are error bars?

Answer 17

Visual indicators of variability in data, often representing 95% confidence intervals.

Question 18

What do overlapping error bars indicate?

Answer 18

No significant difference between conditions.

Question 19

What do non-overlapping error bars indicate?

Answer 19

A significant difference between conditions.

Question 20

What is a scatterplot used for?

Answer 20

To illustrate correlations between two variables.

Question 21

What does a line of best fit represent in a scatterplot?

Answer 21

The trend or relationship between the variables.

Question 22

What are some common mistakes in figures?

Answer 22

Missing titles, unclear labels, inconsistent scales, and misleading representations.

Question 23

How can figures be misleading?

Answer 23

By manipulating axes, omitting scales, or using unclear legends.

Question 24

What is an example of a misleading figure?

Answer 24

Hiding differences by using inappropriate y-axis scales.

Question 25

hat is the purpose of a bar chart?

Answer 25

To compare different groups or conditions visually.

Question 26

Why should error bars be added to bar charts?

Answer 26

To show variability and confidence intervals, making interpretations more reliable.

Question 27

What should be avoided in figures?

Answer 27

Inconsistent formatting, ambiguous labels, and lack of context.

Question 28

What is the role of visual aids in reports?

Answer 28

To summarize data, show trends, and make results easier to understand.

Question 29

Where should visual aids for assessing data go in a report?

Answer 29

In the appendix.

Question 30

Where should visual aids for presenting results go in a report?

Answer 30

In the results section.

Question 31

What is kurtosis’s practical importance?

Answer 31

It indicates the likelihood of outliers, which affects the interpretation of data.

Question 32

How do you determine skewness in R?

Answer 32

Using skewness statistics, histograms with normality curves, or probability density curves.