1. A manufacturer has accumulated the following information from its two factories

	Daily defects in Sydney	Daily defects in Melbourne
Sample mean	4000	4300
Sample standard deviation	100	70
Sample size	100	100

The manager of the Melbourne factory claims there is no significant difference in the number of defects in the two factories. Test the manager's claim at 1% level of significance (assume that the population are normally distributed and have equal variances).