Introduction

Question 1

What is the science of Statistics?

Answer 1

The science of learning from data

Question 2

What is a Population?

Answer 2

A group of objects or individuals about which we wish to draw conclusions.

Question 3

What is a Parameter?

Answer 3

A numeric characteristic of a population.

Question 4

What is the formula to find a Population mean (Mu)

Answer 4

Mu = (1/N)*Sum(from i=1 to N) of x_i
N = size of the population
x_i = value of the i-th value of the population.

Question 5

What is the Population variance (sigma^2)?

Answer 5

This summarizes the natural variability among values of the population.
This can be thought of as the average distance from mu

Question 6

How is the population variance found?

Answer 6

sigma^2 = (1/N)* sum(from i=1 to N) of (x_i - mu)^2

Question 7

How do you find the population standard deviation (aka sigma)?

Answer 7

This is the square root of the population variance (sigma^2). Thus, the pop standard deviation = sqrt(sigma^2)

Question 8

What is the population proportion?

Answer 8

This is the same as mu, except every value (x_i) is given either a 1 or a 0, depending upon whether they possess the characteristic you are looking for.
proportion = (1/N)*Sum(from i=1 to N) of x_i

Question 9

What is a census?

Answer 9

What we call it when data is collected from every single subject in the population.

Question 10

What is a sample?

Answer 10

A subset of the population

Question 11

What is a statistic?

Answer 11

A number that describes a sample. It is used to ESTIMATE the population parameter.

Question 12

Parameter is to population, what…

Answer 12

Statistic is to sample.

Question 13

What formula do we use to find the sample mean (X_bar)?

Answer 13

X_bar = (1/n)Sigma (from i=1 to n) of X_i.
n = sample size
X_i = ith sample value.
aka the sum of the values in a list divided by the number of values in the list.

Question 14

How do we denote the sample variance?

Answer 14

s^2. Like sigma^2, but with the sample!

Question 15

What is the sample proportion, p-hat?

Answer 15

Similar to the population proportion, the sample proportion is found the same as X_bar, but each X_i is given a value of 0 or 1.

Question 16

When is using data from the sample to draw conclusions about the population justified?

Answer 16

When a sample is representative of the entire population (sample looks like the population).
This is called “generalizing our results”.

Question 17

What does it mean if something is random?

Answer 17

The result of a chance process (human choice does not influence the results).

Question 18

What is a Simple random sample (SRS)?

Answer 18

a sample that consists of individuals chosen randomly from the population in such a way that each individual has the same chance of being included in the sample.

Question 19

What is statistical inference?

Answer 19

The science of deducing properties of an underlying population from a sample.

Question 20

What is sampling variability?

Answer 20

Describes the fact that the value of a statistic will vary from sample to sample.

Question 21

A “hat” on a variable denotes what?

Answer 21

That the variable is an estimate!

Question 22

The number of parameters is always equal to…

Answer 22

The number of populations