11MA1 Bivariate & Multivariate Data

Question 1

What are you trying to find with bivariate data?

Answer 1

The relationship between 2 different variables of the same item. e.g. height and weight

Question 2

What do you need to identify from the bivariate question?

Answer 2

The 2 variables, and the population

Question 3

Once you have the bivariate variables what do you do with them?

Answer 3

Find 2 variations and how to manage them for each variable

Question 4

What type of graph is used to display bivariate data?

Answer 4

Scatter plot

Question 5

When analysing bivariate data, what is the first thing you look at?

Answer 5

Type of relationship:
1. Linear (data points follow a straight line)
2. Non-linear (data points follow a curve or have no apparent line)

Question 6

What is the second thing you look at on the scatter plot?

Answer 6

Direction:
1. Positive (trend line going up to right)
2. Negative (trend line going down to right)

Question 7

What is the third (last) thing you look at on the scatter plot?

Answer 7

The strength of the data points (how close the data points are to the trend line)

Question 8

What are the different types of strength?

Answer 8

1. Strong (close to trend line)
2. Moderate (some close, some far)
3. Weak (all points scattered, no pattern)

Question 9

What’s in the conclusion for bivariate data? Reflection, etc.

Answer 9

1. Do your results seem reasonable?
2. Would you expect to get the same results if your investigation was repeated?
   Reflection:
3. How could you improve the reliability of your results?
4. Any other factors that could have affected your results?

Question 10

What must you have in the question for multivariate data?

Answer 10

‘tend(s) to’

Question 11

What are you looking at with multivariate data?

Answer 11

Comparing a variable between 2 groups. e.g. the heights (variable) of boys (group 1) tend to be greater than girls (group 2) of NZ schools.

Question 12

What do you need to identify from the multivariate question?

Answer 12

1. 1 variable
2. (at least) 2 groups
3. the population

Question 13

What are the types of graphs that are used for multivariate data?

Answer 13

1. Dot plot
2. Box and whisker (high box plot)

Question 14

What are the things we look at in a multivariate graph?

Answer 14

1. Centre - median
2. Spread - range and inter quartile range
3. Shape - Bell, right skew, left skew, bimodal, uniform or irregular
4. Interesting features - outlier(s), cluster, gaps

Question 15

When making a call, what is the first case you look for?

Answer 15

Case 1: NO overlapped boxes - can make a call

Question 16

What is the second case you look for if case 1 doesn’t apply?

Answer 16

Case 2: Median of one is outside box of the other sample - can make a call

Question 17

What is the last case you look at if the first 2 don’t apply?

Answer 17

Case 3: Both boxes overlap & medians are inside the other samples box?
Samples 30 & over?
= DBM > OVS / 3 ?
Sample 100 & over?
= DBM > OVS / 5 ?
A claim can only be made if the DBM is greater than the divided OVS.

Question 18

When giving evidence, what are the three things you can say depending on the outcome?

Answer 18

1. I can claim that…
2. I can claim that it is likely that…
3. I don’t have enough information to claim that…

…(group1) is greater than (group2) in the population.