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1. + -15 points DevoreStat9 7.E.036 My Notes Ask Your Teacher A sample of 26 off

ID: 3065995 • Letter: 1

Question

1. + -15 points DevoreStat9 7.E.036 My Notes Ask Your Teacher A sample of 26 offshore oil workers took part in a simulated escape exercise, resulting in the accompanying data on time (sec) to complete the escape. 389 356 359 364 375 424 326 394 403 373 373 371 365 366 364 326 339 393 93 369 375 359 356 403 334 397 A normal probability plot of the n = 26 observations on escape time given above shows a substantial linear pattern; the sample mean and sample standard deviation are 371.00 and 24.28, respectively. (Round your answers to two decimal places.) (a) Calculate an upper confidence bound for population mean escape time using a confidence level of 95%.

Explanation / Answer

SolutionA:

escapetime <- c(389,356,359,364,375,424,326,394,403,373,373,371,365,366,364,326,339,393,393,369,375,359,356,403,334,397)
print(escapetime)
t.test(escapetime)

output:

One Sample t-test

data: escapetime

t = 77.913, df = 25, p-value < 2.2e-16

alternative hypothesis: true mean is not equal to 0

95 percent confidence interval:

361.1931 380.8069

sample estimates:

mean of x

371

95% confidence interval Upper limit=380.81

ANSWER:380.81

Solutionb:

alpha=0.05

alpha/2=0.05/2=0.025

n-1=26-1=25

t crit=2.0595

upper predicction limint=

xbar+tcrit*ssqrt(1+1/n)

=371+2.0595*24.28sqrt(1+1/26)

=421.96

upper prediction bound=421.96

ANSWER:421.96

upper Prediction bound is higher than the upper confidence bound