An industrial supplier has shipped a truckload of teflon lubricant cartridges to an aerospace customer. The customer has been assured that the mean lubricant content of these cartridges is in excess of the 12.1 ml (millilitres) printed on each cartridge.
To determine whether the supplier's claim is true, consider the test, H0: ? = 12.1 against Ha: ? > 12.1, where ? is the true mean content of the cartridges. To check the claim, a sample of n = 34 cartridges are randomly selected from the shipment.
The sample mean teflon content is 12.55 ml and the sample standard deviation is 0.83 ml.
Select the correct test statistic (calculated to 3 decimal places) for this test from the list below.
This will be a t-test statistic because we are standardising the sample mean using an estimate for the standard error (based on s, the sample standard deviation).
a.
2.873
b.
3.161
c.
3.737
d.
2.880