Module 1: Intro To Statistics

Question 1

Unit, individual, element, or case

Answer 1

An object or person on which measurements are taken (single can of dog food)

Question 2

A sample

Answer 2

A set of units chosen in some way from a population (entire set of 100 cans of dog food)

Question 3

An observation

Answer 3

Is a measurement on a unit (the weight if a single can of dog food)

Question 4

A data set

Answer 4

Is a collection of observations from a sample (or, rarely, from a population) (weight in grams of all 100 cans of dog food)

Question 5

A population

Answer 5

Is the set of all units of interest - can be finite or infinite (the set of all cans of dog food that could possible be made - infinite)

Question 6

Sample size

Answer 6

Refers to the number of units in the sample, often denoted as n (n=100)

Question 7

Population size

Answer 7

Refers to the number of units in the population, often denoted as N (N=infinite)

Question 8

A statistic

Answer 8

Is a characteristic of a sample (sample average or mean was 140g)

Question 9

A parameter

Answer 9

Is a characteristic of a population (the mean quantity in gras of the dog food per can is the population mean, which is a parameter)

Question 10

Simple random sampling

Answer 10

Each unit in the population has an equal chance (probability) of being selected, and that probability is 1/N (each Canadian citizen would have a 1 in 36 million (1/N) chance of being selected

Question 11

SRS without replacement

Answer 11

Each unit in the population has an equal chance of being selected, and may be selected only be for the sample

Question 12

SRS with replacement

Answer 12

Part of the sample does not change, even if the unit was previously select to be in the sample

Question 13

Stratified random sampling

Answer 13

The population is divided into sections (‘strata’) and a simple random sample is selected from each stratum - typically done when a population can be divided easily based on some common characteristic (randomly selected from each province and territory)

Question 14

Cluster random sampling

Answer 14

Construction of a sample via the use of groups (‘cluster’) - each cluster has an equal probability of being sampled - once a cluster is selected, a census is conducted within that cluster

Question 15

Voluntary response sampling

Answer 15

Tend to be very biased, as people who respond (or do not respond) tend to fall into specific groups, and people who respond also have very strong opinions about the issue at hand

Question 16

Descriptive statistics

Answer 16

Calculate the summary of values to describe the sample

Question 17

Inferential statistics

Answer 17

Use information gleaned from the sample to try to say something about the unknown population parameter

Question 18

Symbol x

Answer 18

Stands for a list of all of the observations in that sample (x=3,8,10)

Question 19

Symbol i

Answer 19

Is used to denote any position (or index) in the list

Question 20

Symbol E

Answer 20

Green letter, pronounced ‘sigma’ and is used in math as a shorthand for ‘take a sum’ (indicated that the sum will be taken)

Question 21

Symbol i=1

Answer 21

Tells us the starting position for the sum

Question 22

Symbol n

Answer 22

Tells us the position at which to stop summing

Question 23

The sample mean

Answer 23

Denoted as -x (line above x) and is the sum of all of the observations in the sample, divided by the total number of observations in the sample

Question 24

Proportion

Answer 24

Another world for a fraction or percentage, and is another example of a quantity that can be calculated for a sample or for a population- usually expressed in a decimal form