Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone. Twenty-five participants took zinc lozenges, and 23 participants took placebo lozenges. For the placebo group, the mean overall duration of symptoms was x, = 7.7 days, and the standard deviation was 1.4 days. The mean overall duration of symptoms for the zinc lozenge group was x, = 4.2 days, and the standard deviation of overall duration of symptoms was 1.4 days. In USE SALT (a) Calculate x, - x, difference in sample means. X1 - x2 = ( days Compute the unpooled s.e.(x, - x,) standard error of the difference in means. (Round your answer to four decimal places.) s.e.(x - x2) = days (b) Compute a 95% confidence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments. Use the unpooled standard error and use the smaller of n, - 1 and n, - 1 as a conservative estimate of degrees of freedom. (Round the answers to two decimal places.) to days (c) Complete the following sentence interpreting the interval which was obtained in part (b). With 95% confidence, we can say that in the population of cold sufferers represented by the sample, taking zinc lozenges would -Select your answer- v the mean number of days of symptoms by somewhere between and days, compared with taking a placebo. (d) Is the interval computed in part (b) evidence that the population means are different? Fill the blank in the following sentence. |-Select your answer- v evidence that population means are different because it --Select--- 0. Zinc lozenges --Select-- v to be effective in reducing the average number of days of symptoms.
Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone. Twenty-five participants took zinc lozenges, and 23 participants took placebo lozenges. For the placebo group, the mean overall duration of symptoms was x, = 7.7 days, and the standard deviation was 1.4 days. The mean overall duration of symptoms for the zinc lozenge group was x, = 4.2 days, and the standard deviation of overall duration of symptoms was 1.4 days. In USE SALT (a) Calculate x, - x, difference in sample means. X1 - x2 = ( days Compute the unpooled s.e.(x, - x,) standard error of the difference in means. (Round your answer to four decimal places.) s.e.(x - x2) = days (b) Compute a 95% confidence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments. Use the unpooled standard error and use the smaller of n, - 1 and n, - 1 as a conservative estimate of degrees of freedom. (Round the answers to two decimal places.) to days (c) Complete the following sentence interpreting the interval which was obtained in part (b). With 95% confidence, we can say that in the population of cold sufferers represented by the sample, taking zinc lozenges would -Select your answer- v the mean number of days of symptoms by somewhere between and days, compared with taking a placebo. (d) Is the interval computed in part (b) evidence that the population means are different? Fill the blank in the following sentence. |-Select your answer- v evidence that population means are different because it --Select--- 0. Zinc lozenges --Select-- v to be effective in reducing the average number of days of symptoms.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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Transcribed Image Text:Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone. Twenty-five
participants took zinc lozenges, and 23 participants took placebo lozenges. For the placebo group, the mean overall duration of symptoms was x,
7.7 days, and the standard deviation was 1.4 days.
The mean overall duration of symptoms for the zinc lozenge group was x,
4.2 days, and the standard deviation of overall duration of symptoms was 1.4 days.
n USE SALT
(a) Calculate x, - x, difference in sample means.
days
2x - 'x
Compute the unpooled s.e.(x, – x,) standard error of the difference in means. (Round your answer to four decimal places.)
s.e.(x1 - X2) =
days
(b) Compute a 95% confidence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments. Use the unpooled standard error and use the smaller
of n1
1 and n2
1 as a conservative estimate of degrees of freedom. (Round the answers to two decimal places.)
-
to
days
(c) Complete the following sentence interpreting the interval which was obtained in part (b).
With 95% confidence, we can say that in the population of cold sufferers represented by the sample, taking zinc lozenges would -Select your answer- v the mean number of days of symptoms
by somewhere between
and
days, compared with taking a placebo.
(d) Is the interval computed in part (b) evidence that the population means are different? Fill the blank in the following sentence.
-Select your answer- v evidence that population means are different because it ---Select---
v 0. Zinc lozenges ---Select---
to be effective in reducing the average number of days of
symptoms.
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