As the population ages, there is increasing concern about accident-related injur

Question

As the population ages, there is increasing concern about accident-related injuries to the elderly. An article reported on an experiment in which the maximum lean angle—the furthest a subject is able to lean and still recover in one step—was determined for both a sample of younger females (21–29 years) and a sample of older females (67–81 years).

The following observations are consistent with summary data given in the article:

Use the following R code to visualize the data, perform a t test and calculate the 95% CI.
#Data and R Code

boxplot(YF, OF)
t.test(YF, OF, alternative = "greater")
t.test(YF, OF)$conf.int

Compute the test statistic value and find the P-value. (Round your test statistic to three decimal places and your P-value to four decimal places.

t=

p-value=

YF = c( 28, 36, 33, 27, 28, 32, 31, 35, 32, 28, 28, 39, 29, 34, 33, 27, 28, 32, 31, 34) OF = c( 23, 19, 22, 23, 22, 18, 16, 26, 18, 15, 21, 17) As the population ages, there is increasing concern about accident-related injuries to the elderly. An article reported on an experiment in which the maximum lean angle-the furthest a subject is able to lean and still recover in one step-was determined for both a sample of younger females (21-29 years) and a sample of older females (67-81 years). The following observations are consistent with summary data given in the article: Use the following R code to visualize the data, perform a t test and calculate the 95% CI. # Data and R Code YF=E( 28, 36, 33, 27, 28, 32, 31, 35, 32, 28, 28, 39, 29, 34, 33, 27, 28, 32, 31, 34) OF-E( 23, 19, 22, 23, 22, 18, 16, 26, 18, 15, 21, 17) boxplot(YF, OF) ttest(YF, OF, alternative "greater") t.test(YF, OF)$conf.int

Explanation / Answer

The R output is as follows:

t.test(YF,OF,alternative = "greater")

Welch Two Sample t-test

data: YF and OF

t = 9.2265, df = 23.438,

p-value = 1.437e-09

alternative hypothesis: true difference in means is greater than 0

95 percent confidence interval:

9.161877 Inf

sample estimates:

mean of x mean of y

31.25 20.00

> t.test(YF,OF)$conf.int

[1] 8.730247 13.769753

attr(,"conf.level")

[1] 0.95

Based on the output:

Here,

t-stastic=9.226(rounded off to 3 decimal places)

p-value=0.0000(rounded off to 4 decimal places)

Since,p-value<0.005,therefore the conclusion is

Reject H0.The data suggests that the average lean angle for younger women is more than older woman.

The 95% confidence interval is:

(8.73,13.77)(rounded off to 2 decimal places)

Please give a THUMBS UP!!!

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