Question

PLEASE DOUBLE CHECK ANSWER IS CORRECT & DON'T USE HANDWRITTEN ANSWERS. THANK YOU!

A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 411 gram setting. It is believed that the machine is underfilling the bags. A 101 bag sample had a mean of 407 grams with a standard deviation of 15. Assume the population is normally distributed. A level of significance of 0.01 will be used. State the null and alternative hypotheses.

Answer 1

Solution :

This is the left tailed test .

The null and alternative hypothesis is ,

H₀ :   411

H_a : < 411

Test statistic = z

= ( - ) / / n

= (407 - 411) / 15 / 101

= -2.68

Test statistic = -2.68

P(z < -2.68) = 0.0037

P-value = 0.0037

= 0.01

P-value <

Reject the null hypothesis .

There is sufficient evidence to suggest that the bag filling machine works correctly at the 411 gram setting .