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Sleep. In 1908W. S. Gosset published the article "The Probable Error of a Mean" (Biometrika, Vol, 6, pp. 1-25). In this pioneering paper, written under the pseudonym " "Student," Gosset introduced what later became known as Student's t-distribution. Gosset used the following data set, which gives the additional sleep in hours obtained by a sample of 10patients using laevohysocyamine hydrobromide.

a. Obtain and interpret a 95%confidence interval for the additional sleep that would be obtained on average for all people using laevohysocyamine hydrobromide. (Note: x~=2.33hr;s=2.002hr)

b. Was the drug effective in increasing sleep? Explain your answer.

Short Answer

Expert verified

Part (a) We are 95%certain that the mean additional hours of sleep for all patients using laevohysocymine hydrobromide is between 0.90and 3.76hours.

Part (b) we are at least 95%confident that an increase in mean hours of sleep is beneficial. As a result, we can conclude that the medicine was successful in improving sleep.

Step by step solution

01

Part (a) Step 1: Given information

1.90.81.10.1-0.1
4.45.51.64.63.4
02

Part (a) Step 2: Concept

The formula used: The confidence intervalx¯-ta2×sn,x¯+ta2×sn

03

Part (a) Step 3: Calculation

Let μpopulation s.d. be the population mean additional sleep hours, and σbe unknown.

Here the sample sizen=10

We will utilize the t-interval approach to find 95%Clof μas population s.d., σis unknown.

According to one mean t-interval technique, the percent Clof μis 100(1-α)%

x¯-ta2×sn,x¯+ta2×sn

Where tα2is the t-value with area α2to its right, α2is the sample size, andn is the sample size.

Here confidence level =95%

=100×0.95%∴1-α=0.95⇒α=1-0.95⇒α=0.05⇒α2=0.025df=n-1=10-1=9∴Fordf=9,tα=t0025=2.262

04

Part (a) Step 4: Calculation

Given that sample mean x¯=2.33

Sample S.D s=2.002

∴95%Clofμ=x¯-t0.025sn,x¯+t0.025sn=2.33-2.262×2.00210,2.33+2.262×2.00210=(2.33-1.43,2.33+1.43)=(0.8980,3.7620)

i.e., we are 95%certain that the mean additional hours of sleep for all patients using laevohysocymine hydrobromide is between 0.90 and 3.76 hours.

05

Part (b) Step 1: Explanation

We discovered that the mean hour of increased sleep for all patients using laevohysocymine bromide lies between two positive numbers 0.90 hrs and 3.76 hrs based on the 95% confidence interval. As a result, we are at least 95% confident that an increase in mean hours of sleep is beneficial. As a result, we can conclude that the medicine was successful in improving sleep.

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