Doctors are interested in the relationship between the dosage of

Doctors are interested in the relationship between the dosage of a medicine and the time required for a patient's recovery. The following table shows, for a sample of 10 patients, dosage levels (in grams) and recovery times (in hours). These patients have similar characteristics except for medicine dosages.
Doctors are interested in the relationship between the dosage of

a. Estimate the linear regression of recovery time on dosage level.
b. Find and interpret a 90% confidence interval for the slope of the population regression line.
c. Would the sample regression derived in part a be useful in predicting recovery time for a patient given 2.5 grams of this drug? Explain your answer.