Unit 1

Question 1

variable (def)

Answer 1

a characteristic that changes from one individual to another

collect data on variables from individuals

Question 2

categorical variable (def)

Answer 2

takes on values that are category names or group lables

ex. age group, dominat hand, gender, grade level, zipcode

Question 3

Quantitive variable

Answer 3

takes on numerical values for a measured or counted quanity

height, salt level in water, number of candies in a bag, age of building

Question 4

relative frequency is…

Answer 4

propotional to the whole

Question 5

what graphs are used for categorical data

Answer 5

• bar charts (aka bar graphs)
• pie charts

Question 6

Bar charts NEVER ____

Answer 6

touch!

Question 7

What are the cateigories in bar charts called (labels on the bottom)

Answer 7

bins

Question 8

pie charts only display

Answer 8

relative frequencies

Question 9

when comparing groups of diffrent sizes, do you use counts or propotions

Answer 9

proportions

Question 10

what are the 2 types of quanitative variables

Answer 10

1. Discrete
2. Continous

Question 11

Discrete vs. continous variable

Answer 11

Discrete: countable number of values
- ex. number of wins, number of skittles, amount of eruptions in a year
Continous: values that are theortically infinfite (measuring)
- ex. weight of frog, speed of a car

Question 12

What graphs are for quanititve data

Answer 12

• dot plot
• steam and leaf plot
• histogram (most common)
• cumulative graph

Question 13

histogram vs bar chart

Answer 13

histogram
- bars touch
- labels/numbers on line
- quantitive

Bar chart
- space between bars
- labels in the bins
- categorical

Question 14

What does the slope mean in a cumulative graph

Answer 14

the steeper the slope, the more data in the range

no slope = no data

Question 15

What things do you need to include when describing the distrubtion of a quantitative variable/graph

Answer 15

Shape - unimodial, bimodial, symmetical, skews
Outliers
Center - one value that summarizes data
Spread - how the data varies

Question 16

The mean is easily influenced by…

Answer 16

outliers (non resistant)

best for symmetric data

Question 17

Is the median resistant or non-resistant

Answer 17

resistant because it is not influenced by outliers

Question 18

when the data is roughly symmetic, the mean and median are ____

Answer 18

the same (or pretty close together)

Question 19

When the data is skewed left, the mean is ____ than the median

Answer 19

smaller

Question 20

When the data is skewed right, the mean is ____ than the median

Answer 20

larger

Question 21

Percentile

Answer 21

the value that P% of the data is less and or equal to it
- ex. If you take the SAT, and land in the 95% percentile, it means that 95% of the test takers got your score or lower

Question 22

Main points in percentiles

Answer 22

• Q1: first quartile is the 25th percential or the median of the bottom half of data
• Median (overall): 50th percential
• Q3: 75th percentile or the median of the top half of data

Question 23

How to transform the data

Answer 23

1. add/subtract a value
2. multipy all the values

Question 24

how does adding/subtracting (transformations) effect the data

Answer 24

• measures of center
• measures of postion (percentiles/quartiles)

Measures of spead are not effected

Question 25

how does multiplying (transformations) effect the data

Answer 25

effects all areas of statistics
- mean, median, IQR, etc.

Question 26

elements of the 5 number summary

Answer 26

1. min
2. Q1
3. median
4. Q3
5. Maximum

creates boxplot