Lecture 1

Question 1

What is statistics?

Answer 1

A collection of procedure and principles for gaining and analyzing information to educate people and help them make better decisions when faced with uncertainty

Question 2

What is data?

Answer 2

a collection of numbers or other pieces of information to which meaning has been attached

Question 3

Types of Data

Answer 3

Qualitative

Quantitative

Question 4

Qualitative data

Answer 4

• non numeric (can sometimes have numbers but cannot be classified as numeric)
• nominal: categories without order
• ordinal: categories with order (universal - ex: 1 agree 5 disagree)

Question 5

Types of Quantitative

Answer 5

• ratio (discrete, continuous)

- interval (discrete, continuous)

Question 6

Ratio

Answer 6

differences AND ratios are meaningful, natural starting point (meaningful 0)

• discrete: countable number of possible values
• continuous: infinite number of possible values
  ex: 1:10 girl to guy ratio

Question 7

Interval

Answer 7

differences are meaningful, ratios are NOT meaningful

• continuous: infinite number of possible values
• discrete: countable number of possible values
  ex: Temperature (can’t say 40 is 2x hotter than 20 degrees)

Question 8

Stem-plot

Answer 8

a quick and easy way to put a LIST of numbers into order while getting a picture of their shape

Question 9

Truncate

Answer 9

used in stem-plot, drop off numbers instead of rounding them

Question 10

Histograms

Answer 10

Pictures related to stem-plots

• uses ranges
• does not list every value
• good for large number sets

Question 11

Mean

Answer 11

sum of all the data values, divided by the number of data values (AVERAGE)

Question 12

Mode

Answer 12

Value that occurs most often

Question 13

Median

Answer 13

middle value of the data set when it has been arranged in ascending order (smallest to highest), often termed central tendency when there are out liars

Question 14

Range of data set

Answer 14

difference between the highest and lowest values in the set

Question 15

Measure of spread

Answer 15

Measures of spread describe how similar or varied the set of observed values are for a particular variable (data item)

Question 16

Measure of shape

Answer 16

a distribution of data item values may be symmetrical or asymmetrical

• normal distribution
• skewed districution

Question 17

Right skew

Answer 17

• when the tail on the right side of the histogram is longer than the tail on the right and the mean is higher than the median

Question 18

Left skew

Answer 18

• when the tail on the left side of the histogram is longer than the right and the mean is lower than the median

Question 19

Bin-Width

Answer 19

how big of an interval to use for each bar in a histogram

Question 20

Range

Answer 20

max-min

Question 21

Standard Deviation

Answer 21

roughly the average distance of values from their mean

Question 22

Variance

Answer 22

standard deviation squared

Question 23

percentile

Answer 23

a value below which a particular percentage of data points lie (median - 50th percentile)

Question 24

Quartiles

Answer 24

divide the order date into 4 equal sized groups

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