Question

uppose you have purchased a filling machine for candy bags that is supposed to fill each bag with 16 oz of candy. Assume that the weights of filled bags are approximately normally distributed. A random sample of 10 bags yields the following data (in oz): 15.87, 16.02, 15.78, 15.83, 15.69, 15.81, 16.04, 15.81, 15.92, 16.10 On the basis of this data, can you conclude that the mean fill weight is actually less than 16 oz? Let LaTeX: \alpha=5\%α = 5 %. What would be the appropriate null and alternative hypothesis?

Answer 1

Null, H0: μ ≥ 16

Alternative ; H1: μ < 16

reject H0

Explanation:

Null, H0: μ ≥ 16

Alternative ; H1: μ < 16

To compute the test statistic :

We need the sample mean and sample standard deviation :

15.87, 16.02, 15.78, 15.83, 15.69, 15.81, 16.04, 15.81, 15.92, 16.10

Using calculator :

Sample mean, m = 15.887

Standard deviation = 0.13

Test statistic :

(m - μ) / s/sqrt(n)

(15.887 - 16) / 0.13/sqrt(10)

-0.113 / 0.0411096

= - 2.749

Tcritical at 95%

Tn-1, 0.025

T10,0.025 = 2.262

Since the test statistic value is less than the critical value, reject H0