Question

The director of research and development is testing a new medicine. She wants to know if there is evidence at the 0.1 level (α=0.1) that the medicine relieves pain in less than 420 seconds. For a sample of 51 patients, the mean time in which the medicine relieved pain was 400 seconds. Assume the population standard deviation is known to be 75.

What is the calculated value of the test statistic (Z*)?

-5.9765

0.1478

-1.9044

1.5678

3.6784

Answer 1

Solution :

This is the left tailed test .

The null and alternative hypothesis is ,

H0 :   =420

Ha : <420

Test statistic = z

= ( - ) / / n

= (400 -420) / 75/ 51

Test statistic = -1.9044