Question

Suppose the sales team at Apple is interested in investigating whether the colours of the iPod Touch have any impact on sales. To test this, they use five different colours for the new iPod Touch. The following table shows the number of each colour of 1335 iPods sold during the first month at one retailer. At the 1% significance level, test whether the number of iPods sold in each colour is uniform. Keep 4 decimal places for intermediate calculations.

iPod colour	iPods sold
Grey	310
White	235
Pink	290
Lime	280
Teal	220

Answer 1

Solution:

The null and alternative hypotheses are:

H0: The number of iPods sold in each color is uniform.

Ha: The number of iPods sold in each color is not uniform.

Under the null hypothesis, the test statistic is:

Where: