Data analysis

Question 1

Conditions for chi square

Answer 1

1. Independence
2. 5+ Sample size
3. > 1 degree of freedom

Question 2

What do rows in data represent?

Answer 2

Observations

Question 3

What do columns in data represent

Answer 3

Variables

Question 4

Experimental Study

Answer 4

Manipulation of an independent variable to measure the impact on a dependent variable (control group etc.)

Question 5

Observational study

Answer 5

Study of the relationship between variables with no manipulation/intervention

Question 6

Where does the explanatory variable belong

Answer 6

Horizontal axis

Question 7

Where does the response variable belong

Answer 7

Vertical axis

Question 8

What is sample standard deviation

Answer 8

Variance

Question 9

Calculate the probability (A AND B)

Answer 9

P(A) x P(B)

Question 10

Calculate the probability (A OR B)

Answer 10

P(A) + P(B) - P(A AND B)
- e.g. (0.3 + 0.7) - (0.7 x 0.3) = 0.79

Question 11

Calculate the Probability A given B

Answer 11

If the events are independent, the probability is just P(A) - the occurrence of B does not affect the probability of A

Question 12

A given B - conditional

Answer 12

P(A and B)/P(B)

Question 13

Bayes Theorem

Answer 13

P(A/B) = P(B/A)P(A) / P(B)

Question 14

Z score formula

Answer 14

x-mean / standard deviation

Question 15

Binomial distribution

Answer 15

• Fixed number of independent trials
• 2 possible outcomes ‘success’ and ‘failure’

Question 16

T-distribution

Answer 16

t = x - μ / s / root(n)

x - sample mean
μ - population mean
s - sample SD
n - Sample size

Question 17

How to calculate degrees of freedom?

Answer 17

Sample size (n) - 1

Question 18

What does mutually exclusive mean?

Answer 18

When P(A and B) = 0
Events are mutually exclusive when they cannot happen at the same time, and share no basic outcomes

Question 19

Events are independent if…

Answer 19

The occurrence of one has no impact on the probability of the other occurring

Question 20

Two tailed or One tailed test

Answer 20

• One tailed - only want to know either lower or higher
• Two tailed - testing for a difference in either direction

Question 21

Standard error

Answer 21

• Standard deviation / (root)Sample

Question 22

Key notation

Answer 22

𝑥- sample mean
𝑝- sample proportion
𝜇- population mean
𝑝- population proportion
𝑠- sample standard deviation
𝜎- population standard deviation
𝑛- sample size
𝛽- population regression coefficient
𝑏- sample regression coefficient
Σ- summation operator

Question 23

Extrapolation

Answer 23

• When you predict about something outside the range of data you already have, based on the value of the predictor variable
• e.g. using the adults weight for the baby weight model

Question 24

Residual

Answer 24

Observed value - predicted value

Question 25

Linear probability model

Answer 25

- Odds always between 0 and , which represent the probability of them occurring (yngkid = 0,1) -