Unit 1

Question 1

what is the study of statistics?

Answer 1

is the set of methods for obtaining, organizing, summarizing, presenting and analyzing data

Question 2

what is data?

Answer 2

a set of measurements or observations taken on a group of objects
ex. the people taking the survey

Question 3

what is a population?

Answer 3

the totality of individuals or units about which we want information
ex. all people in manitoba taking the survey

Question 4

what is a variable?

Answer 4

a characteristic or property of an individual or unit

Question 5

what are some examples of variables?

Answer 5

hair color
height
your grade in this course
marital status

Question 6

what is a sample?

Answer 6

a subset of units in a population that we examine in order to gather information about the population

Question 7

what does categorical ordinal mean?

Answer 7

data follows a natural order and the order makes sense

Question 8

what are examples of categorical nominal?

Answer 8

gender (female or male)
marital status (married, widowed, divorced)

Question 9

what are quantitative variables?

Answer 9

have values that are a count or are obtained by measurement
it makes sense to take the average

Question 10

what are examples of quantitative variables?

Answer 10

distance ran in 45 mins
measurement in cm of all the students in this classroom
square footage of your house

Question 11

what does the distribution of a variable tell us?

Answer 11

what values it takes and how often it takes on these values

Question 12

what type of charts can we use with categorical variables?

Answer 12

bar charts
pie charts

Question 13

what type of charts can we use with quantitative variables?

Answer 13

histograms
timeplots

Question 14

what is the difference between a bar chart and a histogram?

Answer 14

in a bar chart the bars don’t touch
in a histogram the bars do touch

Question 15

what do pie charts give us a visual representation of?

Answer 15

relative frequency
proportion of the observed values

Question 16

what does a frequency distribution table look like

Answer 16

31 37 40 44 49 50 51 53 56 56
62 64 67 67 68 68 69 70 71 72
73 73 74 75 77 78 78 81 82 84

Question 17

what are the two types of quantitative variables?

Answer 17

continuous variable
discrete variable

Question 18

what values can a continuous variable take?

Answer 18

any value within a given range
ex. weight and distance

Question 19

what values can a discrete variable take?

Answer 19

only take a countable number of values
ex. number of children in a family and the number of days of rain in a month

Question 20

what do we look for in respect to histograms? (5)

Answer 20

shape
any gaps
peaks (center)
spread (how variable the values of the data are)
outliers (observations that fall away from the overall pattern)

Question 21

what are the 3 types of shapes a histogram can have?

Answer 21

approximately symmetric
skewed to the left
skewed to the right

Question 22

why would we use a timeplot?

Answer 22

if we gather data that comes to us in a sequence over a period of time

Question 23

what is a trend?

Answer 23

a time series with a persistent long term rise or fall

Question 24

what is seasonal variation?

Answer 24

a pattern that repeats itself at certain intervals

Question 25

what do we use to measure the centre of our data?

Answer 25

we use a measure of central tendency

Question 26

what are the two measures of central tendency?

Answer 26

mean median

Question 27

mean

Answer 27

average value

Question 28

median

Answer 28

in a set of ordered data the median is the value that splits the data into two equal parts

Question 29

what is the sum of deviations always equal to?

Answer 29

0

Question 30

what is an outlier?

Answer 30

a point that falls far away from the majority of the data

Question 31

is the median robust (resistant) or not robust (not resistant) to outliers?

Answer 31

median is robust to outliers (not affected) mean is affected by outliers

Question 32

when does symmetric distribution occur?

Answer 32

when the mean and median are equal (exactly symmetric is ideal)

Question 33

when does skewed to the left occur?

Answer 33

when the mean is less than the median

Question 34

when does skewed to the right occur?

Answer 34

when the mean is greater than the median

Question 35

how do we calculate the measure of spread?

Answer 35

by using the range

Question 36

what is the range?

Answer 36

R a measure of spread and is simply calculated as maximum-minimum

Question 37

what are characteristics about range? (3)

Answer 37

the larger the value of R the more variable the data are R measures the length of the interval containing 100% of the data Range is affected by outliers

Question 38

what is IQR (interquartile range)?

Answer 38

Q3 - Q1

Question 39

when do we use the five number summary?

Answer 39

when describing our distributions with numbers

Question 40

what does the five number summary consist of?

Answer 40

minimum first quartile (Q1) median third quartile (Q3) maximum

Question 41

what does a boxplot consist of?

Answer 41

rectangle that is formed by using the quartiles and whiskers extending from the rectangle to the maximum and minimum values

Question 42

what is the standard deviation?

Answer 42

written as s measure of spread around the mean

Question 43

what is the variance?

Answer 43

written as s^2 the square of the standard deviation

Question 44

what is degrees of freedom?

Answer 44

n-1 in the denominator

Question 45

when do we use deviation as a measure of spread?

Answer 45

when x̄ is the measure of centre

Question 46

when does the standard deviation equal zero?

Answer 46

when there is no spread about the mean

Question 47

is standard deviation affected by outliers?

Answer 47

yes!