Math IB Stats

Question 1

Discrete data

Answer 1

Fixed to certain values; no gaps between data values

Question 2

Continuous data

Answer 2

Not fixed to certain values; can occupy a continuous range

Question 3

Reliable data

Answer 3

If you can repeat the data and obtain similar results

Question 4

Sufficient data

Answer 4

When there is enough data to support your conclusions

Question 5

Population

Answer 5

The entire group that you want to draw conclusions about

Question 6

Sample

Answer 6

Subset of population; group of individuals from the population that will give info about the population as a whole

Question 7

Sampling technique: convenience

Answer 7

Most easily accessible members of a population

Question 8

Sampling technique: simple random

Answer 8

Randomly choose members - equal chance for everybody

Question 9

Sampling technique: systematic

Answer 9

Pick at a fixed interval — eg every 6th person

Question 10

Sampling technique: stratified

Answer 10

Divide group into groups (stratas) based on shared characteristics, then sample from the groups

Question 11

Sampling technique: quota

Answer 11

Stratified sampling, but sample from each stratum is proportional and to the size of each stratum

Question 12

Bar chart

Answer 12

For discrete data; has gaps in between the bars

Question 13

Histogram

Answer 13

No gaps in between bars; for continuous data

Question 14

Skew

Answer 14

Where the majority of the data is located (shape)

Question 15

Histogram skew

Answer 15

Left (-): most data is on right side - left tail
Normal: equally distributed
Right (+): most data is on left side - left tail

Question 16

Mode

Answer 16

Value that occurs the most

Question 17

Modal

Answer 17

For grouped data — can’t find mode so we would say the modal range

Question 18

Bimodal; no mode

Answer 18

Bimodal - 2 modes in set of data
No mode - all numbers appear only once

Question 19

Mean

Answer 19

The average

Question 20

Median

Answer 20

The middle data value when data set is arranged in order of size (if even data set — median is avg of two middle numbers)

Question 21

Range

Answer 21

Max - min

Question 22

Quartiles

Answer 22

Divides data into quarters
- 1st: 25% of data below it
- 2nd: the median and has 50% of data below and above
-3rd: 75% below

Question 23

Interquartile range (IQR)

Answer 23

Difference between Q3 and Q1

Question 24

Lower quartile

Answer 24

Q1

Question 25

Middle quartile

Answer 25

Q2

Question 26

Upper quartile

Answer 26

Q3

Question 27

Outlier for boxplot

Answer 27

Outliers are 1.5xIQR above Q3 or below Q1

Question 28

Cumulative frequency

Answer 28

The sum of all previous frequencies up to the current point

Question 29

Percentile

Answer 29

A value below which a certain percentage of observations lie

Question 30

Percentile rank

Answer 30

Calculate by dividing #of values below ___ by total # of values

Question 31

Variance

Answer 31

How far a data point is spread from the mean (sigma squared)

Question 32

Standard deviation

Answer 32

Square root of variance

Question 33

Bivariate data

Answer 33

Study of relationships between to sets of data

Question 34

Correlation

Answer 34

When change in x corresponds to change in y

Question 35

Causation

Answer 35

When one event is the result of the a occurrence of another event

Question 36

Pearson product moment correlation coefficient (r)

Answer 36

Measure of the correlation strength between two variables. Between -1 and 1 ( can equal)

Question 37

R value

Answer 37

0 is weakest. 1 is strongest. (-) values mean there is a negative correlation.

Question 38

Line of best fit

Answer 38

Straight line drawn though the center of a group of points plotted on a scatter diagram

Question 39

Interpolation

Answer 39

Predictions inside the domain your data points are in

Question 40

Extrapolation

Answer 40

Predictions outside the domain of your data

Question 41

Draw line of best fit

Answer 41

Find mean point which line will go through. Equal number of points above and below line.

Question 42

Residual

Answer 42

The vertical distance between data pints and a graph of a regression line

Question 43

Least square regression line

Answer 43

Has the smallest possible value for the sum of squares of the residual

Question 44

Regression line y on x

Answer 44

Y=ax+b A = change on y for each change in x B = y int

Question 45

Binomial distribution elements:

Answer 45

- fixed number of trials - only two outcomes, success or failure - constant probability each trial - trials are independent

Question 46

Probability - with replacement

Answer 46

Elements in sample space remains unchanged (e.g if you pull a card out of a deck, you put it back)

Question 47

Probability - without replacement

Answer 47

Items are not returned to the sample space (e.g if you pull a card out from a deck, you leave it out, changing probabilities for next time)