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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 nine patients. The effective period of

the tranquilizer for each patient (in hours) was as follows: 2.7;2.8;3.0;2.3;2.3;2.2;2.8;2.1;and2.4.

a.i.x=__________ii.sx=__________iii.n=__________iv.n1=__________

b. Define the random variable Xin words.

c. Define the random variable Xin words.

d. Which distribution should you use for this problem? Explain your choice.

e. Construct a 95%confidence interval for the population mean length of time.

i. State the confidence interval.

ii. Sketch the graph.

iii. Calculate the error bound.

f. What does it mean to be 鈥95% confident鈥 in this problem?

Short Answer

Expert verified

(a) The result are as follows:

1.x=2.511.

2. sx=0.3179

3. n=9

4. n-1=8

(b) For the effective length of X, the time for the tranquillizer.

(c) From a sample of 9patients, the mean time for the tranquillizer for the effective length is X.

(d)The parameter is tn-1, and the distribution is t.

t9-1=t8.

(e) The results are as following,

1.CI=(2.2667,2.7555)

2.Shown in graph

3. EBM=0.2444

(f) If a group of nine patients were sampled, 90%of the sample would represent the real population mean length of time.

Step by step solution

01

Explanation (a)

i. To find the mean and standard deviation, use the formulas below.

To open the setup editor, hit STAT followed by the number 5and then Enter. We must enter each value and then press the arrow to calculate, resulting in the final output seen below.

In the mean time,x=2.511

ii. The sample length of time's standard deviation, sx=0.3179

iii. The number of patients who were used in study, n=9.

iv. If the total number of patients involved in the study is n=9than,n-1=8.

02

Explanation (b) 

For the effective length of X, the time for the tranquillizer.

03

Explanation (c)

From a sample of9 patients, the mean time for the tranquillizer for the effective length is X.

04

Explanation (d)

The parameter is tn-1, and the distribution is t.

t9-1=t8.

05

Explanation (e)

1. Using the $T I-83$ calculator, calculate the confidence interval. The confidence interval's output,

CI=(2.2667,2.7555)

ii. The graph is follows below:

iii. The error bound is calculated from the formula,

EBM=tn-12sn

EBM=t9-10.0520.317989

EBM=0.2444

06

Explanation (f)

If a group of nine patients were sampled, 90%of the sample would represent the real population mean length of time.

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Most popular questions from this chapter

What is meant by the term 90%confident鈥 when constructing a confidence interval for a mean?

a. If we took repeated samples, approximately 90%of the samples would produce the same confidence interval.

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c. If we took repeated samples, approximately 90%of the confidence intervals calculated from those samples would

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