Class 3 Spring 🌷

Question 1

What are the three measures of Central Tendency?

Answer 1

Mean, median, mode

Question 2

What are the measures of Dispersion?

Answer 2

Range, IQR, variance, standard deviation

Question 3

What type of data is the mode primarily used for?

Answer 3

Categorical data

Question 4

What is the definition of ‘mode’?

Answer 4

The value with the most occurrences in the data set

Question 5

What is the formula to calculate the range?

Answer 5

Highest number - Lowest number

Question 6

What is variance represented by?

Answer 6

s²

Question 7

What is the relationship between variance and standard deviation?

Answer 7

Standard deviation is the square root of variance

Question 8

What does the Interquartile Range (IQR) measure?

Answer 8

Dispersion related to the median

Question 9

How is the median represented in a Box-and-Whisker plot?

Answer 9

A dark line denoting the median

Question 10

What percent of data falls between Q1 and the median in a Box-and-Whisker plot?

Answer 10

50%

Question 11

What is a characteristic of a right (positive) skewed distribution?

Answer 11

Tail on the right side

Question 12

Fill in the blank: The _______ is the average squared distance from the mean.

Answer 12

Variance

Question 13

What is the typical distribution of data within one standard deviation of the mean?

Answer 13

About 70%

Question 14

What type of data is IQR used with?

Answer 14

Numerical data

Question 15

What does a Box-and-Whisker plot’s whiskers represent?

Answer 15

Data outside of the box attempting to capture the spread

Question 16

True or False: Outliers are defined by hard-and-fast rules.

Answer 16

False

Question 17

What is the purpose of identifying outliers in data?

Answer 17

Useful for various reasons in statistics

Question 18

What are the shapes/modalities that a distribution can have?

Answer 18

Uniform, unimodal, bimodal, multimodal

Question 19

What does skewness describe in a dataset?

Answer 19

Asymmetry of the distribution

Question 20

Common examples of right skewed data include _______.

Answer 20

People’s incomes, house prices, number of accident claims

Question 21

What is the measure of centrality that is primarily used for numerical data?

Answer 21

Mean and median

Question 22

What is the main question to answer when describing a dataset regarding central tendency?

Answer 22

Where is the ‘middle’ of the dataset?

Question 23

What is the primary measure of dispersion for categorical data?

Answer 23

Range

Question 24

What does the term ‘deviation’ refer to in statistics?

Answer 24

Distance from the mean

Question 25

What is the first step in building a Box-and-Whisker plot?

Answer 25

Drawing a line denoting the median

Question 26

Fill in the blank: The _______ is the typical deviation of observations from the mean.

Answer 26

Standard deviation

Question 27

What percent of data typically falls within two standard deviations of the mean?

Answer 27

About 95%

Question 28

What statistical notation is used for the standard deviation of a sample?

Answer 28

s

Question 29

What is a common method to visualize median and IQR?

Answer 29

Box-and-Whisker plots

Question 30

What is the significance of the first and third quartiles in a Box-and-Whisker plot?

Answer 30

They define the boundaries of the box representing the middle 50% of the data

Question 31

What is a common example of right/positively skewed data?

Answer 31

People's incomes ## Footnote Other examples include mileage on used cars, reaction times, house prices, and number of accident claims.

Question 32

What is a common example of left/negatively skewed data?

Answer 32

Number of fingers ## Footnote Most people have ten fingers, but some may lose one or more. The age at death in wealthy countries is also negatively skewed.

Question 33

What are two top choices for visualizing skewed data?

Answer 33

* Histograms * Box-and-whisker plots

Question 34

In a skewed distribution, where does the mode typically lie?

Answer 34

Under the peak of the distribution.

Question 35

What happens to the mean in a skewed distribution?

Answer 35

The mean gets pulled in the direction of the skew.

Question 36

What is the relationship between skewness and the difference between the mean and median?

Answer 36

The greater the skewness, the greater the difference between the mean and the median.

Question 37

If the data are skewed, which measure of central tendency may not provide a good estimate?

Answer 37

The mean.

Question 38

Fill in the blank: The median and IQR are only sensitive to numbers near _______.

Answer 38

Q1, the median, and Q3.

Question 39

What is the interquartile range (IQR)?

Answer 39

A measure of statistical dispersion.

Question 40

Which measure is likely more useful for understanding a typical individual loan?

Answer 40

The median.

Question 41

Which measure is likely more useful for understanding the total amount needed for 1,000 loans?

Answer 41

The mean.

Question 42

True or False: In very skewed data, the mean provides a good estimate of the data center.

Answer 42

False.

Question 43

What happens to the mean and median in right-skewed data?

Answer 43

Median < Mean.

Question 44

What happens to the mean and median in left-skewed data?

Answer 44

Mean < Median.

Question 45

What is the summary statistic for centrality of data in symmetrical data?

Answer 45

Mean.

Question 46

What is the summary statistic for data spread?

Answer 46

Standard deviation.

Question 47

What statistical tools may not be usable with skewed data?

Answer 47

* t-test * ANOVA

Question 48

What does the median represent in skewed data?

Answer 48

A better estimate of the center than the mean.

Question 49

What is a characteristic of robust statistics in relation to skewness?

Answer 49

They are stable in the presence of extreme observations.

Question 50

What are examples of potentially skewed datasets?

Answer 50

* Sea Turtle Sizes * Stats Test Scores * Swim Times