Question 1 - A-Level Maths

Exam Board	Edexcel
Module	S4 (Statistics 4)
Year	2015
Session	June
Topic	Hypothesis test of a normal distribution

The Sales Manager of a large chain of convenience stores is studying the sale of lottery tickets in her stores. She randomly selects 8 of her stores. From these stores she collects data for the total sales of lottery tickets in the previous January and July. The data are shown below

Store	A	B	C	D	E	F	G	H
January ticket sales \(( \boldsymbol { \pounds } )\)	1080	1639	710	1108	915	1066	1322	819
July ticket sales \(( \boldsymbol { \pounds } )\)	1113	1702	831	1048	861	1090	1303	852

Use a paired \(t\)-test to determine whether or not there is evidence, at the \(5 \%\) level of significance, that the mean sales of lottery tickets in this chain's stores are higher in July than in January. You should state your hypotheses and show your working clearly.
State what assumption the Sales Manager needs to make about the sales of lottery tickets in her stores for the test in part (a) to be valid.