Question

The reacttimes data set has 50 observations of human reaction times to a physical stimulus.
The reaction times are named Times and arranged in increasing order below.
0.12 0.30 0.35 0.37 0.44 0.57 0.61 0.62 0.71 0.80 0.88 1.02 1.08 1.12 1.13 1.17 1.21 1.23 1.35
1.41 1.42 1.42 1.46 1.50 1.52 1.54 1.60 1.61 1.68 1.72 1.86 1.90 1.91 2.07 2.09 2.16 2.17 2.20
2.29 2.32 2.39 2.47 2.60 2.86 3.43 3.43 3.77 3.97 4.54 4.73
1. Find the mean and median of Times without using R. You may use your calculator.
2. Import reacttimes into your workspace as a data frame with a single variable Times.
Attach the reacttimes data frame to your workspace with
> attach(reacttimes)
Then calculate the mean of Times by using R's mean( ) function and the median with R's
median( ) function.
3. Find the 60th percentile of Times without using R. There may be more than one accept-
able answer.
4. Find the 60th percentile of Times using R's quantile( ) function.
5. Find the 40th percentiles of mydata and mydata[-21] by hand and also by using R.
6. Find the 5% trimmed mean of Times.
7. Find the five number summary of Times.
8. The 40th value Times(40) of the reaction time data is 2.32. Change it to 232.0 and
recalculate the mean and median. You can make the change in R by

> Times[40]=232.0

Answer 1

Civen xi on ,0.30, 0.35, 3,0.44,0.61,062, 0-11 0 30 078,,13 , 1.12, 1.13 ,1 1t, 1.14 , 1.23 1-35, 1, 1.42, 142, 146, 1.So, I.52, Igq,1. 1.G1 1-68 , l'n, l.3G, l'go, 131 , 2.07, 2.09, 2-16, 2.14, ono 2.2 232 2.39, 24, 2. Go, 1. C, 3.43,3.43,3.77, 3.94 4.54 , 4.73 To ta l =17. 12 mean f times--= 1.1424 = the size of (5-2+1) th ite = the Size of C25.5 jth İrerザー term item - size of (s jth iter pertentilee se have o Catculate Coth percentie.

observotHion th ะ L30-G | Observation : (30 )th absenvation + 6 (31)th observation 3oth obser vation F 1.72 to .86 1.12 z 1.72t 084 observation (1o.4) th obs":@oft, ObSnto.4/(2リ obsn 141 4L1 42 -1.41 141 +0.4 Co.01) P4o 1414

R RGui (32-bit) File Edit View Misc Packages Windows Help 3RR Console R Untitled -R Editor times-C (0.12,0.30,0.35,0.37,0.44,0.57,0.61,0.62,0 t1es a=mean (times) > times-c (0.12,0.30,0.35,0.37,0.44, 0.57,0.61,0-62,0.71,0.80,0.8,1.02,1.08,1.12,1.13,1.17,1.21,1.23,1.35, 1.41,1.4 > times 1] 0.12 0.30 0.35 0.37 0.44 0.57 0.61 0.62 0.71 0.80 0.88 1.02 1.08 1.12 1.13 [16] 1.17 1.21 1.23 1.35 1.41 1.42 1.42 1.46 1.50 1.52 1.54 1.60 1.61 1.68 1.72 31] 1.86 1.90 1.91 2.07 2.09 2.16 2.17 2.20 2.29 2.32 2.39 2.47 2.60 2.86 3.43 [46] 3.43 3.77 3.974.54 4.73 b-median (times) c-quantile (times,0.60) a-mean (times) d=quantile ( times, 0·40) 1 1.7424 > b-median (times) >b [1 1.53 >c-quantile (eimes,0.60) e-mean ( times, trim-0 .05) tivenun (times) sunnary (times3) sunmary (fivenum(times) ) timest401 232.0 t1es mean (times) median times) 60% 1.776 > d-quantile (eimes,0.40) > d 40% 1.416 > e-mean (times, trim-0.05) 1] 1.683261 > fivenum (times) 1] 0.12 1.08 1.53 2.20 4.73 summary (times) Min. 1st Qu Median Mea 3rd Qu 0.120 1.090 1.5301.742 2.192 4.730 Max summary (Eivenum (times)) Min. 1st Qu Median Mea 3rd Qu 0.120 1.080 1.530 1.932 2.200 4.730 Max > times[401-232.0 > times 1 0.12 0.30 0.35 0.370.44.57 0.61 0.62 0.71 0.80 11 0.881.02 1.08 1.12 1.13 1.17 1.21 1.231.35 1.41 [21 1.2 1.42 1.46 1.50 .52 1.54 1.60 1.61 1.68 1-72 rP ^恤缶40) ENG 12:13 AM