In: Statistics and Probability
A pharmaceutical company makes tranquilizers. It is assumed that the distribution for the length of time they last is approximately normal. Researchers in a hospital used the drug on a random sample of 9 patients. The effective period of the tranquilizer for each patient (in hours) was as follows: 2.6; 2.9; 3.0; 2.3; 2.3; 2.2; 2.8; 2.1; and 2.4. NOTE: If you are using a Student's t-distribution, you may assume that the underlying population is normally distributed. (In general, you must first prove that assumption, though.)
A. Round your answers to two decimal places.
x-bar =
sx =
Enter an exact number as an integer, fraction, or decimal.
n =
Enter an exact number as an integer, fraction, or decimal.
n − 1 =
B. Which distribution should you use for this problem? (Enter your answer in the form z or tdf where df is the degrees of freedom.)
C. Construct a 95% confidence interval for the population mean length of time.
(i) State the confidence interval. (Round your answers to two decimal places.)
(ii) Sketch the graph.
a/2=
C.L.=
(iii) Calculate the error bound. (Round your answer to two decimal places.)