Patients with chronic kidney failure may be treated by dialysis, in which a mach
ID: 3060053 • Letter: P
Question
Patients with chronic kidney failure may be treated by dialysis, in which a machine removes toxic wastes from the blood, a function normally performed by the kidneys. Kidney failure and dialysis can cause other changes, such as retention of phosphorus, that must be corrected by changes in diet. A study of the nutrition of dialysis patients measured the level of phosphorus in the blood of several patients on six occasions. Here are the data for one patient (in milligrams of phosphorus per deciliter of blood).
The measurements are separated in time and can be considered an SRS of the patient's blood phosphorus level. Assume that this level varies Normally with
= 0.9 mg/dl.
(Round your answers to three decimal places.)
(a) Give a 95% confidence interval for the mean blood phosphorus level.
(b) The normal range of phosphorus in the blood is considered to be 2.6 to 4.8 mg/dl. Is there strong evidence that this patient has a mean phosphorus level that exceeds 4.8?
Explanation / Answer
The statistical software output for this problem is:
One sample Z confidence interval:
: Mean of variable
Standard deviation = 0.9
95% confidence interval results:
Hence,
a) 95% confidence interval:
(4.563, 6.003)
b) No, there is not strong evidence of a mean phosphorus level that exceeds 4.8.
Variable n Sample Mean Std. Err. L. Limit U. Limit Data 6 5.2833333 0.36742346 4.5631966 6.0034701