Chapter 2

Question 1

What is coding?

Answer 1

Changing adapting the value of a variable
From x to x+1

Question 2

What is lowercase x and what is uppercase x?

Answer 2

x = actual values
X = random set of values

Question 3

What is the difference between variables in statistics compared to in algebra?

Answer 3

x can represent multiple objects/people
Like a set

Question 4

What is central tendency? How do we find the mean in frequency table and grouped data?

Answer 4

CT = mode, mean, median
Mean = x(with line on top) = (sigma x freq x x)/ sigma x freq
Can use statistics mode on calculator

Question 5

What does sigma mean?

Answer 5

Sum of values

Question 6

What is the formula for position of median? Discrete & Grouped

Answer 6

DISCRETE:
n/2
if a decimal then round up, if whole use halfway between this and next item
GROUPED:
n/2

Question 7

What is the formula for median of grouped data? What is this called?

Answer 7

Median position - ((lowest frequency (cumulative frequency of one before)/class frequency) x class width) + start interval
Linear interpolation

Question 8

What do you do if there are gaps between class widths?

Answer 8

Extend the class interval
10 - 12 -> 9.5 - 12.5
13 - 15 -> 12.5 - 15.5

Question 9

Definition of variance?

Answer 9

Measure of spread that takes into account all values

Question 10

What are the two equations for variance?

Answer 10

(Sigma x^2/n) - mean^2
Sigma (x - mean)^2 / n

Question 11

What is the standard deviation?

Answer 11

Variance square rooted

Question 12

What is the pneumonic for variance and the meaning?

Answer 12

msmsm = mean of the squares minus the square of the mean

Question 13

What is the formula for variance for grouped frequency?

Answer 13

(Sigma fx^2 / sigma f) - mean^2

Question 14

What is the molecular formula? Empirical formula? Displayed formula?

Answer 14

Molecular = Actual number of atoms in a molecule
Empirical = simplest whole number ratio of elements in compound
Displayed = shows how atoms are bonded ( c - c)