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

15, 3.5, 12, 6, 7.5, 3, 4, 16, 17.5, 21

What are the null and alternative​ hypotheses?

Determine the test statistic. ____

Fail to Reject or Reject? There is ___ evidence to conclude that the mean lead concentration for all such medicines is ___ 15 μ​g/g

Answer 1

H0: >= 15

Ha: < 15

From the sample data,

= 10.55 , S = 6.5720

Test statistics

t = ( - ) / ( S / sqrt(n) )

= (10.55 - 15) / ( 6.5720 / sqrt(10) )

= -2.14

t critical value at 0.10 significance level with 9 df = -1.383

Since test statistics t < -1.383 , Reject H0

There is sufficient evidence to conclude that the mean lead concentration for all such medicines is

less than 15 g / g