Salt-free diets are often prescribed to people with high blood pressure. The data shown below were obtained from an experiment designed to estimate the reduction in diastolic blood pressure as a result of following a salt-free diet for two weeks.
Before: 112 108 97 90 104 89 94 95 100 98
After: 107 104 98 90 103 91 94 94 102 96
Let d = diastolic blood pressure before diet d-diastolic blood pressure after diet. Assume diastolic readings to be normally distributed. The sample mean difference of the sample is 0.8 and the sample standard deviation of the difference is 2.348. Test whether a salt-free diet for two weeks is effective in reducing the diastolic blood pressure.