## Part 1 – The Pilot Study

A pilot study (sometimes called a pretest) is a preliminary test to see if there is a line of enquiry to investigate further.

You will be testing the following hypothesis in your pilot study:

The taller you are the heavier you are

Taking a Sample

There are the 1183 students at Mayfield High School. The table shows the number of students in each year group for males and females.

Year Group

Boys

Girls

Total

Year 7

151

131

282

Year 8

145

125

270

Year 9

118

143

261

Year 10

106

94

200

Year 11

84

86

170

For your pilot study you must consider each of the 10 groups in the school (i.e Year 7 Girls, Year 7 Boys, Year 8 Girls etc) to test your initial hypotheses. To do this you will need samples from each group as the whole school is too large to work with. You should take a stratified random sample of 100 students for your pilot study.

Stratified Sample - A stratified sample takes a proportional number from each group in the population so that each group is fairly represented. This is necessary when producing graphs or statistical calculations on more than one section of the population together.

E.g. If there were 150 Year 7 girls in a school with 1000 students and you wanted to take a stratified sample of 100 students in total, then use the formula:

No. of each group in sample =

E.g.No. of Year 7 girls = x 100 = 15 students