Interpreting Data

Question 1

Types of quantitative data

Answer 1

Discrete
Continuous

Question 2

Types of qualitative data

Answer 2

Nominal
Ordinal

Question 3

What is the difference between nominal and ordinal date

Answer 3

Nominal unordered, ordinal ordered

Question 4

2 measures of location

Answer 4

Median
Mean

Question 5

2 measures of spread

Answer 5

Standard deviation
Interquartile range

Question 6

Standard deviation

Answer 6

quantity expressing by how much the members of a group differ from the mean value for the group
Average squared distance form mean, squared

Question 7

When should median and interquartile range be used instead of mean and standard deviation

Answer 7

When sample has outliers

Question 8

What is the term for distribution of many random variables as a symmetrical bell-shaped graph

Answer 8

Gaussian distribution (normal distribution)

Question 9

How does the number of values within any specified number of standard deviations above or below the mean vary with sample size in a Gaussian distribution

Answer 9

No change

Question 10

What percentage of values lies within 1.64 standard deviations of the mean in a Gaussian distribution

Answer 10

90%

Question 11

How many standard deviations above or below the mean do 95% of the values in a Gaussian distribution lie

Answer 11

1.96

Question 12

Standard error what does standard error measure

Answer 12

Statistical accuracy of an estimate

Question 13

Standard error of the mean

Answer 13

Standard deviation of the distribution of all possible sample means

Question 14

What does a 95% confidence interval mean

Answer 14

We are 95% sure the true value lies within a certain range

Question 15

What is the most commonly used confidence interval

Answer 15

95%

Question 16

How does the 95% range size change as sample size increases

Answer 16

Stays the same

Question 17

How does confidence interval change as sample size increases

Answer 17

Narrows

Question 18

What is the correlation between 2 variables when r= 1, 0, and -1

Answer 18

1 - perfect positive correlation
0 - no correlation
-1 - perfect negative correlation

Question 19

What distribution of data is spearman’s rank used on

Answer 19

Non linear mono tonic relationship - non Gaussian

Question 20

What does spearman’s rank assess

Answer 20

how well the relationship between two variables can be described using a monotonic function

Question 21

What is used to calculate spearman’s rank

Answer 21

Difference in ranks between 2 ranked datasets

Question 22

Regression curves

Answer 22

Linear
Quadratic
Cubic
Exponential growth
Exponential decay
Sigmoid

Question 23

What can be used to determine if an observed difference is due to chance

Answer 23

Confidence intervals
P values

Question 24

What does p value assess

Answer 24

how likely you are to have found a particular set of observations if the null hypothesis were true

Question 25

Degrees of freedom

Answer 25

Number of values free to vary

Question 26

When can t tests be used

Answer 26

When 2 measurements are made on the same group

Question 27

Can t tests be performed on non Gaussian distributions

Answer 27

No - non Parametric test used instead

Question 28

When should a fishers exact test be used instead of chi squared test

Answer 28

Sparse data

Question 29

What do chi squared tests assess

Answer 29

Difference in actual data from predicted results