Question

Listed below are the lead concentrations in mu​g/g measured in different traditional medicines. Use a 0.05 significance level to test the claim that the mean lead concentration for all such medicines is less than 14 mu​g/g. 18     3.5     16.5     21     11.5     8.5     8     17.5     8.5     3 What are the null and alternative​ hypotheses?

Answer 1

Here claim is that the mean lead concentration for all such medicines is less than 14 mu​g/g.

As null hypothesis always have equality sign, hypothesis is vs

As n=10 and population standard deviation is not known, we will use t distribution to find test statistics

Using sample we get and

Hence test statistics is

Now P value is TDIST(1.2,9,1)=0.1304>alpha=0.05

So we fail to reject the null hypothesis

Hence we do not have sufficient evidence to support the claim that mean lead concentration for all such medicines is less than 14 mu​g/g.