CH 1

Question 1

Sample Mean Equation

Answer 1

x̄ = ( Σ xi ) ÷ n
(Average)

Question 2

Sample Standard Deviation Equation

Answer 2

s = √[ (∑(xi − x̄)^2) / (n - 1) ]

Question 3

Define Sample Variance

Answer 3

s^2 = (∑(xi − x̄)^2) / (n - 1)

Question 4

Define Outlier Points

Answer 4

Points that are much larger or smaller than the rest.

Question 4

Sample Median

Answer 4

The sample median is the middle number when the values are ordered from smallest to largest.
Note: When odd find the mean of the two middle numbers.

Question 5

Define Mode

Answer 5

The sample mode is the most frequently occurring value in a sample.

Question 6

Define Range

Answer 6

The range is the difference between the largest and smallest values in the sample.

Question 7

Define Quartiles

Answer 7

Quartiles divide the sample into fourths.

Question 8

Define Percentile

Answer 8

Percentile is the percentage of values in a sample that fall below a given value. It describes how a value compares to other values from the same sample.

Question 9

Define Statistics

Answer 9

1. Summarizing /describing /visualizing data.
2. Using collected data to draw inference about unknown outcomes.
3. Exploring the mathematical foundation which support the inference we draw.

Question 10

Define Parameter

Answer 10

A numerical summary of a population.

Question 11

Define Population

Answer 11

The collection of all subjects of interests

Question 12

Define Sample

Answer 12

A sample is a subset of a population containing the objects or outcomes that are actually observed.

Question 13

Define Subject

Answer 13

A person, place or thing from which we collect.

Question 14

Define Variable

Answer 14

A characteristic of a subject which varies in a non-random way.

Question 15

Random Variable

Answer 15

A variable whose outcome is the result of some random process.

Question 16

Define Simple Random Sample

Answer 16

A simple random sample of a size n is a sample chosen by a method in which each collection of n population items is equally likely to compromise the sample, just as in a lottery.

Question 17

Define the four types of variables.

Answer 17

1. Categorical(Qualitative): Variables which are naturally measured as labels.
   +Nominal: Labels with no natural rank/order
   +Ordinal: Labels with natural rank/order
2. Numerical Random Variable(Quantitative): Variables that are naturally recorded/collet as numbers.
   +Continuous Random Variable: Number which can theoretically take on any values in a certain interval.
   +Discrete Random Variable: Discrete random variables can only take on a finite number of values

Question 19

Define Randw

Answer 19

The maximum difference in values of data set.

Question 20

Define Interquartile Range (IQR)

Answer 20

Difference between Q_1 and Q_3

Question 21

Define Sample Variance

Answer 21

Typical squared deviation from the mean.

Question 22

Define Sample Standard Deviation

Question 23

Categorical data

Answer 23

For summarizing categorical data have /frequency relative frequency. (Sample population)
+frequency: number of sample items that fall in same category
+relative frequency = frequency/samplesize. Always between 0 and 1. Percentage number.