Descriptive Statistics

Question 1

Which comes first? Descriptive or Inferential?

Answer 1

1. Descriptive
2. Inferential

Question 2

Descriptive Statistics ?

Answer 2

Descriptive statistics is a means of describing features of a data set by generating summaries about data samples.

Question 3

Inferential Statistics?

Answer 3

Inferential statistics use measurements from the sample of subjects in the experiment to compare the treatment groups and make generalizations about the larger population of subjects.

Question 4

What are the measures of central tendency?

Answer 4

1. Arithmetic Mean
2. Median
   3.Mode

Question 5

Arithmetic Mean?

Answer 5

Average Value

Question 6

What is arithmetic mean suitable for?

Answer 6

Suitable for symmetrical distributions

Question 7

Symmetrical Graph Shape and distribution ?

Answer 7

Bell-shaped & Normal Distribution

Question 8

Asymmetrical Graph Shape and distribution ?

Answer 8

Distribution skewed to right
Positively skewed

Question 9

What affects the mean of asymmetrical graphs?

Answer 9

The outliers

Question 10

Median?

Answer 10

The median is the value in the middle of a data set, meaning that 50% of data points have a value smaller or equal to the median and 50% of data points have a value higher or equal to the median.

Question 11

Why is median not affected by outliers?

Answer 11

Median is a robust measure thus not affected but outliers

Question 12

What is median ideal for?

Answer 12

Asymmetrical Distribution

Question 13

Why is median ideal for asymmetrical data?

Answer 13

It is a robust measurement and not affected by outliers

Question 14

Measures of central tendency?

Answer 14

Central tendency is a descriptive summary of a dataset through a single value that reflects the center of the data distribution. Along with the variability (dispersion) of a dataset, central tendency is a branch of descriptive statistics. The central tendency is one of the most quintessential concepts in statistics.

Question 15

Which measure of central tendency do you use for a/symmetrical data?

Answer 15

Symmetrical Data-arithmetic mean

Asymmetrical Data-Median

Question 16

Mode?

Answer 16

Most frequent value

Question 17

Why is mode not affected by outliers?

Answer 17

It is a robust measurement

Question 18

Robust measurement?

Answer 18

Robust measures of scale are methods that quantify the statistical dispersion in a sample of numerical data while resisting outliers. The most common such robust statistics are the interquartile range (IQR) and the median absolute deviation (MAD).

Question 19

How can we know that a graph is symmetrically distributed ?

Answer 19

The measures of central tendency will be close together.

For asymmetrical distribution has measures of central tendency spaced out

Question 20

Measures of spread?

Answer 20

1. Variance and standard deviation
2. Range
   3.Interquartile Range

Question 21

Variance?

Answer 21

Average squared distance from the mean

Variance is a measure of dispersion, meaning it is a measure of how far a set of numbers is spread out from their average value.

Question 22

Why don’t we use variance?

Answer 22

Variance gives you a squared unit and thus not easy to use and apply

Question 23

Standard Deviation?

Answer 23

Square root of the variance

The standard deviation is the average amount of variability in your data set. It tells you, on average, how far each score lies from the mean.

Question 24

Why is standard deviation ideal to use?

Answer 24

-Doesn’t have squared root
-Affected by outliers
-

Question 25

Which kind of distribution do we use variance and standard deviation for?

Answer 25

We use standard deviation + mean for symmetrical distribution. We do not use for asymmetrical distribution.

Question 26

When are statistics stronger for variance and standard deviation?

Answer 26

When the standard deviation is low

Question 27

What is standard deviation a good decriptor of?

Answer 27

Good descriptor of spread for normal, symmetrical, distributions

Question 28

Range?

Answer 28

Range is between the maximum and minimum values?

Question 29

Range equation?

Answer 29

Range=Maximum value-Minimum Value

Question 30

Range>Interquartile Range?

Answer 30

Interquartile range

Question 31

Interquartile range?

Answer 31

-25th and 75th percentiles -covers 50% of values - the interquartile range (IQR) is a measure of statistical dispersion, which is the spread of the data.

Question 32

Nominal Data: -Mode -Median, IQR ,Range -Median, SD

Answer 32

Mode: Yes Median: No(can't establish logical order) Mean, SD: NO

Question 33

Ordinal Data: -Mode -Median, IQR ,Range -Median, SD

Answer 33

Mode: Yes Median: Yes(data has order) Mean, SD: No

Question 34

Interval Data: -Mode -Median, IQR ,Range -Median, SD

Answer 34

Mode: Yes Median: Yes Mean, SD: Yes

Question 35

Ratio Data: -Mode -Median, IQR ,Range -Median, SD

Answer 35

Mode: Yes Median: Yes Mean, SD: Yes

Question 36

Why do we prefer to use IQR more than range

Answer 36

When measuring variability, statisticians prefer using the interquartile range instead of the full data range because extreme values and outliers affect it less. Typically, use the IQR with a measure of central tendency, such as the median, to understand your data's center and spread.