key defintions

Question 1

what are the measures of central tendancy

Answer 1

Mean median mode

Question 2

what are the measures of dispersion

Answer 2

Range, Variance, SD, Q1,Q2,Q3, Correlation coefficient, Coefficient of determination, Upper fence, lower fence

Question 3

what do the upper and lower fence mean

Answer 3

the upper and lower fences represent the cut-off values for upper and lower outliers in a dataset

Question 4

SD and variance?

Answer 4

Variance is a measure of how far a set of data is spread out. It is the average of the squared differences from the mean of the data. In other words, variance measures the average distance of each data point from the mean of the dataset. It is denoted by the symbol σ^2.

Standard deviation is the square root of the variance. It measures the amount of variation or dispersion of a set of data from the mean. Standard deviation is denoted by the symbol σ.

Question 5

do variance and SD measure the same thing?

Answer 5

idk

Variance is a measure of the average squared deviation of the data from the mean. It is a mathematical calculation that is used to quantify the amount of spread or variability in a dataset. In IB Maths, it is denoted by the symbol σ^2.

Standard deviation, on the other hand, is the square root of the variance and is a measure of the spread or dispersion of the data. It is a widely used measure of variability and is denoted by the symbol σ.

Question 6

if r = 0

Answer 6

regression line is horizontal

Question 7

in histograms the heights of each boxes are ….

Answer 7

proportional to the frequency of the values of the intervals

Question 8

mode class refers to the whole thing of

Answer 8

100 <=x,=200 for example

Question 9

measures of dispersion generally tell us

Answer 9

how spread out the data is and a measure of its variability

Question 10

dont forget that

Answer 10

Q1 represents that 25% of data is below this value and same with the rest for ex

Q3 represents that 75% of data is below this #

Question 11

what is the 5 number summary

Answer 11

min, Q1,Q2,Q3, max

Question 12

Mean deviation means?

Answer 12

average distance of ALL OF THE DATA POINTS from the mean/avg

Question 13

diff between mean deviation and standard deviation

Answer 13

Mean deviation measures the average distance of each data point from the mean. (important) The mean deviation uses the absolute values of the differences from the mean unlike standard deviation that just squares the differences.

SD measures the amount of variation or dispersion of a set of data from the mean.

Question 14

define population variance

Answer 14

the sum of the squared differences divided by the population

Question 15

what is the names for the r values

0-0.25

0.25-0.5

0.5 - 0.75

0.75-1

Answer 15

1) very weak model
2) weak model
3)moderate
4) strong

Question 16

what are the two ways to find the mean points

Answer 16

using calc, 2) finding the POI of the lines y on x and x on y using substitution

Question 17

how are spearmans rank and pearsons product moment correlation different

Answer 17

Spearman’s rank correlation coefficient and Pearson’s product moment correlation coefficient measure the strength and direction between two variables

Pearson’s correlation is used when both variables are continuous and the relationship is linear,

while Spearman’s correlation is used when the variables are ordinal or the data is not normally distributed.

Question 18

What is the r value of the equation of y on x and x on y when they are equivalent equations and why

Answer 18

the r value is either r=1 or r=-1 and this is because of the perfect fit with the line of best fit and there is no deviation from the line as (1,1), (2,2) and so on.

Question 19

define interpolation and extrapolation

Answer 19

interpolation is making predictions insde the domain (accurate)

extrapolation is making predictions outside your data points (inaccurate)

Question 20

define an outlier

Answer 20

Outliers are extreme data values that do not fit with the rest of the data.

Question 21

why do we rank values in spearman’s rank coefficient

Answer 21

Reduces the impact of outliers: Ranking the values can reduce the impact of outliers or extreme values in the data.

Makes the data more comparable: Ranking the values makes the data more comparable, particularly when the data has different scales or units of measurement

Handles non-linear relationships: By ranking the values, we can detect non-linear relationships between variables.

Improves the accuracy of the correlation coefficient: Ranking the data can improve the accuracy of the correlation coefficient by reducing the impact of measurement errors or inconsistencies in the data.

Question 22

when is spearmans rank coefficent better than pearsons product moment correlation

Answer 22

when the relationship between two variables is nonlinear or ordinal, Spearman’s rank correlation coefficient is better than Pearson’s product moment correlation coefficient.