Statistical Analysis - Create questions and analyis

Bloggs.Karen.72160.A3.1234567.doc 1

72160 Statistical Analysis: Assignment 3

This is an example of how your Assignment 3 should look. Do not copy and paste from

this document – you need to use your own words! A blank version of the template can

be found on the Online Campus in the Assessments section. Save it to your computer, fill in

your project details and upload the file under the Assignment 3 link on the Online Campus.

Student name: Karen Bloggs Student number: 1234567

Title

The title of my project is:

1. Introduction

Give a brief description of your project. Discuss why it is important to investigate your aims and why

the project is of general interest. This should be covered briefly here and in more depth on the actual

project.

2. Aims

Specify two or more aims. These should be written in clear statistical language.

For example:

1. to test if the mean value of a variable differs for two populations (specify the variable and

populations)

2. to estimate the proportion of …… from a stated population

3. to investigate if there is a linear relationship between … and… (specify the two numeric

variables )

4. to investigate if there is any association between … and… (specify the two categorical

variables )

Bloggs.Karen.72160.A3.1234567.doc 2

3. Methodology

3.1 Data collection and sampling method

State the source of your data (give the link if this comes from a website) and how the data was

collected. You need a simple random sample from a larger population or a stratified random sample

(e.g. divide your population into men and women and randomly sample from each). State what your

population is, your method of sampling and your sample size.

Note:

1. A sample size of about 100 is suitable, but if the dataset is already a sample of 200, then use

all 200.

2. If you get your data from a website, you may need to make some assumptions about how the

data was collected and how the sampling was done.

3. Data which has already been summarised, such as weekly totals of phone calls, cannot be

used. You need a sample of individual phone calls.

4. Data which is in time series order (e.g. weekly sales for the last two years) is not a random

sample and can only be used in conjunction with other data.

5. Possible sources for data are given on the 72160 page of the Online Campus under

Assignment 3 in the Assessments section.

3.2 Variables

Name your variables and state whether they are numeric or categorical variables. Give the range of

possible values each variable can take.

Note: your dataset must contain at least one numeric variable.

4. Analysis

Specify your planned analysis to answer Aim 1.

This should include the exploratory work (summary statistics, check for outliers), graphs you will use

and a form of inference.

For example, if the aim is to compare exam marks for men and women you might say your analysis

will include:

 Histograms of men’s marks and women’s marks with comments

 5 number summary of marks for men and women with comments

 Side by side boxplots of marks with comments

 Check for outliers using 1.5IQR rule and comment on outlier values

 Mean and standard deviation of men and women’s marks with comments

Bloggs.Karen.72160.A3.1234567.doc 3

 Normal quantile plots of men and women’s marks with comments

 A two sample t test to compare mean marks for men and women*

 A confidence interval for the difference between the two means

*Think carefully about whether a two-sample t test or a matched-pairs t test is appropriate.

Repeat for Aim 2.

Note:

1. When doing tests of significance you are expected to show hypotheses, comment on validity, test statistic, degrees of freedom, P-value and conclusion in your final project and include the output in the appendix. See Formatting Instructions found under Assignment 4 in the

Assessments section of the Online Campus.

2. We have not covered inference for regression in this course, so if you are doing regression you will be expected to find and discuss the following: scatterplot, R, R

2 , regression equation

and residual plot, but we do not expect t-tests or confidence intervals when addressing this

aim.

5. Data

Insert your dataset (or part of it; at least 5 observations) here. Make sure the columns are clearly

labelled with the variable names you have referred to above. Do not include any confidential

information, such as names.

For example:

ID number Gender Age Income ($) Location

1 Male 23 45000 Wellington

2 Female 45 87000 Wellington

3 Male 40 55500 Auckland

4 Female 25 28400 Christchurch

5 Female 33 37650 Auckland

Important Note: See the Assignment 4 Formatting Instructions in under Assignment 4 in Assessments section of the Online Campus. Also refer to the relevant information in your Assessment

booklet (pink pages or in Assessments section of the Online Campus).

Stuck for data?

You will find some suggested data sources under Assignment 3 in Assessments section of the Online

Campus.