Question

Listed below are the lead concentrations in μ g/g measured in different traditional medicines. Use a 0.10 significance level to test the claim that the mean lead concentration for all such medicines is less than 15 μ g/g. 22 14.5 10 11 7.5 10 8 3 12 19

What are the null and alternative hypotheses?

What is the test statistic

Identify the P VALUE

Conclusion

Answer 1

H0: >= 15

Ha: < 15

From given sample data,

= 11.7 , S = 5.5837

Test statistics

t = - / S / sqrt(n)

= 11.7 - 15 / 5.5837 / sqrt(10)

= -1.87

From T table,

With test statistics t = -1.87 and df = 9 ,

p-value = 0.0472

Since p-value < 0.10 level, we have sufficient evidence to reject the null hypothesis.