Statistical Tests

Question 1

What are the two types of variables/data

Answer 1

-Qualitative (Categorical)
-Quantitative

Question 2

Qualitative (Categorical) variables include (3)

Answer 2

-dichotomous (binary)
-nominal
-ordinal

Question 3

Dichotomous (binary) data is where

Answer 3

-Every observation is in one of two categories (yes/no)
-represented as a percentage

Question 4

Nominal data is

Answer 4

-three or more categories/classes have no inherent ordering (labelled as numbers)
-represented as a bar chart or % in each category

Question 5

Ordinal data is

Answer 5

-Three or more categories with the categories having some inherent order
-represented as a bar chart or % of subjects in each category

Question 6

Two types of Quantitative variables/data

Answer 6

-discrete (discontinuous or count)
-continuous

Question 7

Discrete data (counts)

Answer 7

-Have only values as whole numbers (integers)
-represented as a histogram

Question 8

Continuous data

Answer 8

-have any value defined within a range
-represented in a histogram or box & whisker plot

Question 9

What type of data is pulse rate

Answer 9

Quantitative: Discrete/Count

Question 10

What type of data is eye color

Answer 10

Qualitative: Nominal

Question 11

What type of data is daily milk yield per cow

Answer 11

Quantitative: Continuous

Question 12

What type of data is number of lesions

Answer 12

Quantitative: Discrete/Count

Question 13

What type of data is pregnancy status of each cow

Answer 13

Qualitative: Dichotomous/Binary

Question 14

What type of data is number of puppies per litter

Answer 14

Quantitative: Discrete/Count

Question 15

Central tendency includes

Answer 15

-mean
-median
-mode

Question 16

Measures of spread includes (4)

Answer 16

-range
-percentile
-variance
-standard deviation

Question 17

Common types of graphs are

Answer 17

-bar charts
-histograms
-box plots
-scatter plots

Question 18

Bar charts are used for

Answer 18

Nominal or Ordinal data

Question 19

Histograms are used for

Answer 19

Continuous or Count data

Question 20

Box & Whisker plots are used for

Answer 20

Continuous data

Question 21

Scatter Plots are used for

Answer 21

Continuous data

Question 22

Normal distribution is

Answer 22

-bell shaped
-variables are evenly distributed

Question 23

Right skewed distribution means the tail is on the ___ while left skewed means the tail is on the ___

Answer 23

Right; left

Question 24

In normal distribution,

Answer 24

The mean, median, and mode are very similar

Question 25

Skewed distribution,

Answer 25

The mode and median may be similar but the mean will be a poor indicator of central tendencies

Question 26

The range is

Answer 26

The difference between largest value minus lowest value

Question 27

The box in box and whisker plot represents ___ while the whiskers represent ___

Answer 27

Upper and lower quartiles (and median); range

Question 28

Binary, nominal, and ordinal data are all

Answer 28

Qualitative

Question 29

The standard error or the sample mean (SEM) is used to

Answer 29

Calculate confidence intervals

Question 30

What is the interpretation of a 95% confidence interval

Answer 30

“The interval from __ to __ has a 95% chance (probability) to contain the true population mean”

Question 31

The null hypothesis is

Answer 31

The hypothesis that there is no difference between groups (easier to disprove)

Question 32

The alternative hypothesis is

Answer 32

The hypothesis that there is a difference between the groups

Question 33

The goal is to disprove the ___ hypotheses

Answer 33

Null

Question 34

The p-value is the

Answer 34

The probability of data occurring if the null hypotheses is true

Question 35

If p is small

Answer 35

-null hypotheses is unlikely to be true and it is rejected “Difference is statistically significant”

Question 36

If p is large

Answer 36

-data is consistent with the null hypotheses Ie. no strong evidence

Question 37

Chi square test is

Answer 37

Used to compare proportions

Question 38

One sample t-test is used

Answer 38

-To test whether the mean of a sample/population is different from a particular value -normal distribution -one group

Question 39

Two sample t-test

Answer 39

-used to test equality of the means of two populations -normal distribution -two comparison groups

Question 40

Paired t-test

Answer 40

-used to test equality of the means of two samples/populations, when the observations are paired samples -normal distribution -two comparison groups that are paired/related

Question 41

Analysis of Variance (ANOVA)

Answer 41

-used to test equality of the means of 2+ populations -normal distribution

Question 42

Wilcoxon’s Signed rank test

Answer 42

-test whether the median of a sample or population is different from a particular value -similar to t-test one sample -not normally distributed -one group

Question 43

Wilcoxon’s Rank Sum Test (3)

Answer 43

-used to test equality of the mean ranks of two samples/populations -not normally distributed -similar to two sample t-test

Question 44

Wilcoxon’s Signed rank test - two matched pairs

Answer 44

-used to test the difference between two samples/populations using matched pairs -not normally distributed -similar to paired t-test

Question 45

Kruskal-Wallis test

Answer 45

-used to test equality of the mean ranks of 2+ samples/populations -not normally distributed

Question 46

Kaplan-Meier curve with Log-Rank test

Answer 46

-outcome must be time ie. survival

Question 47

Cox Proportional Hazards Regression

Answer 47

Uses time and the outcome ie. comparing survival time

Question 48

Logistic Regression

Answer 48

-yes/no outcome