Question

A fertilizer distributor sells fertilizer in 10 kg bags. A customer feels that the distributor sells underweight bags. To support his hunch, he purchases 8 bags of fertilizer. They have an average weight of 9.65 kg with standard deviation 0.7 kg. Does the customer have a case against the distributor? Test using α = 0.05.

Answer 1

Solution :

= 10

= 9.65

s = 0.7

n = 8

This is the left tailed test .

The null and alternative hypothesis is

H0 :   = 10

Ha : < 10

Test statistic = t

= ( - ) / s / n

= (9.65 - 10) / 0.7 / 8

= -1.41

P (t< -1.41 ) = 0.1007

P-value = 0.1007

= 0.05  

0.01007 > 0.05

Do not reject the null hypothesis .

There is insufficient evidence to suggest that