In your first after college, you are working a trainee appraising real estate fo
ID: 3232051 • Letter: I
Question
In your first after college, you are working a trainee appraising real estate for property tax purposes in the tax tax assessor's job a which will also be office. After six months' training, given an exam in which you appraise 13 properties, appraised by an expert. You like your job, so you're hoping to do well. Ir there is no statistically significant difference between the sample means of your appraisals and the expert's, you will be given an increase in salary. If there is a statistically significant difference (at the 0.05 level), you will be fired. Appraisal results (000s) Property You Expert 175 Note that this is a PAIRED-DIFFERENCE design, where each property is 179 appraised twice, and it is the DIFFERENCE between you and the expert 181 185 157 159 that counts. 185 186 Our text refers to this as "dependent samples." 193 188 156 157 Subtraction is the first step, then you work with just the differences. Remember that the t-test uses a differences, but that ties are 10 187 discarded in the two nonparametric tests. 199 197 12 13 169 169 Print this page first, then fill in the answers by hand.Explanation / Answer
R CODINGS :
a = c(176,179,185,157,185,193,156,177,200,188,180,199,169)
b = c(175,179,181,159,186,188,157,172,198,187,177,197,169)
t.test(a,b, paired=TRUE)
OUTPUT :
Paired t-test
data: a and b
t = 2.2957, df = 12, p-value = 0.04051
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
0.07439347 2.84868345
sample estimates:
mean of the differences
1.461538
SIGN TEST NOW :
CODING IN R :
a = c(176,179,185,157,185,193,156,177,200,188,180,199,169)
b = c(175,179,181,159,186,188,157,172,198,187,177,197,169)
data<-c(a,b)
data
t.test(a,b, paired=TRUE)
new<-order(data)
library(BSDA)
SIGN.test(new, conf.level=0.90)
OUPUT :
One-sample Sign-Test
data: new
s = 26, p-value = 2.98e-08
alternative hypothesis: true median is not equal to 0
90 percent confidence interval:
9.262904 17.737096
sample estimates:
median of x
13.5
Conf.Level L.E.pt U.E.pt
Lower Achieved CI 0.8314 10.0000 17.0000
Interpolated CI 0.9000 9.2629 17.7371
Upper Achieved CI 0.9245 9.0000 18.0000