Question

a brand of water-softener salt comes in packages marked “net weight 40 lbs”. The company that packages the salt claims that the bags contain an average of 40 lbs of salt and that the standard deviation of the weight is 1.5lbs. Assume that the weights are normally dostributed.

if you bought 1 bag and it weighs 39 lbs, would you consider the evidence that the company’s claim is incorrect?

Answer 1

The null and alternate hypothesis are:

H0:

Ha:

Let the level of significance be .

The test statistic value is given by:

Since this is a two tailed test, so the the critical values are:

and

Since the test statistic value lies between these two values, so it lies in the acceptance region. Thus, we accept the null hypothesis H0.

Thus we say and the company's claim is correct.