4 credits. an understanding of the difference between sample and population is required at all...

4 credits

Level 1 Multivariate Unit

An understanding of the difference between sample and population is required at all levels.

Investigate a given multivariate data set using the statistical enquiry cycle

Data

The provided data set is a sample from a named population.

You choose both the category variable and the numerical variable.


Data

You choose both the category variable and the numerical variable.


Problem

You pose your own investigative question.

The question must involve

a comparison,

include the variable to investigate,

specify the groups being compared,

the population and

the direction of the comparison.


Problem

A suitable question would be

‘Do New Zealand year 11 boys tend to be taller than New Zealand year 11 girls?’.


Analysis

You will create both a dot plot and a box and whisker plot.


Analysis

The dot plot enables you to ‘see’ the distributions and discuss the features they notice.


Analysis

The box and whisker plot enables you to make a ‘call’ as evidence to answer your question for the given population.


Analysis

When ‘discussing features of distributions comparatively’ use the visual evidence in the displays.


Analysis

Comments about the features need to be comparative and in context of the numeric variable.


Analysis

You could observe:a larger spread in the middle 50% of the times to walk to school for year 10 students than for year 8 students that there is an overlap in the middle 50% of index finger lengths for year 11 girls and boys


Analysis

You could observe:that there is an overlap in the middle 50% of index finger lengths for year 11 girls and boys


Analysis

You could observe:that the middle 50% of heights of year 11 boys is higher up the scale than the middle 50% of heights of year 11 girls.


Analysis

You must discuss features in context. For example, identify the two groups being compared and refer to the variables by giving the numerical values and their units


AnalysisYour discussion would need to be justified with supporting evidence from the displays and measures and there must be an understanding of the feature that is discussed.


ConclusionAnswer the posed investigative question and make an informal inference about the population


ConclusionThe answer to the investigative question needs to be consistent with the analysis that has occurred.

There needs to be evidence to justify the conclusion made.


ConclusionIt is expected that the conclusion is consistent with the approach of looking at the medians and the relative location of the ‘boxes’ (middle 50% of the data).


ConclusionA small difference between the medians relative to the overall visual spread might not enable a call to be made and this would need to be identified.

In this case the consistent conclusion would be that it is not possible to make a call.


4 credits. an understanding of the difference between sample and population is required at all...

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