Question

A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 444 gram setting. It is believed that the machine is underfilling the bags. A 39 bag sample had a mean of 436 grams. Assume the population standard deviation is known to be 19. Is there sufficient evidence at the 0.01 level that the bags are underfilled?

Answer 1

Solution :

= 444

=436

=19

n = 39

This is the two tailed test .

The null and alternative hypothesis is ,

H0 :    = 444

Ha :     444

Test statistic = z

= ( - ) / / n

= (436 -444 ) / 19 / 36

= -2.629

Test statistic = z = -2.63

P-value = 2 *0.0043 =0.0086

= 0.01

P-value <

0.0043 < 0.01

Reject the null hypothesis .

There is sufficient evidence to suggest that