Two laboratories A and B carry out independent estimates of fat content in ice cream made by a firm. A sample taken from each batch gives the following fat content:
Batch No - 1 2 3 4 5 6 7 8 9 10
Lab A _ 7 8 7 3 8 6 9 4 7 8
Lab B _ 9 8 8 4 7 7 9 6 6 6
Is there a significant difference between the mean fat-content obtained by the two laboratories A and B?