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library(statsr)
## Warning: package 'statsr' was built under R version 4.0.3
library(dplyr)
## Warning: package 'dplyr' was built under R version 4.0.2
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
library(ggplot2)
x <- rnorm(100, mean = 100, sd = 20)
mean(x)
## [1] 100.4846
sd(x)
## [1] 23.09992
getwd()
## [1] "C:/Users/Jerome/Documents/0000_Work_Files/0000_Coursera/Statistics_with_R_Specialization/Course_1_Probability_&_Data/Week_4_Thinking_plus_Course_Materials"
head(x)
## [1]  71.51319 115.47459 116.34087 120.89071  57.23384  95.65640
write.table(x=x, file ="x.csv", row.names = FALSE)
random <-read.csv("random.csv", header = TRUE)
#x <-read.csv("x.csv", header = TRUE)

So what have I learned about reading and writing files? When i created random, it had 100 observations. When i wrote it, it was

a null file. But when i opened it in Excel from the folder, it had data; it was not null. I then read it into r, and then i could write it again to save it. So when you generate a random number vector, you must read it in before you can write it, i think. At the end i’ll try it w/ kobe_streak.

#mean(random$random_no)
#mean(x$x)
#sd(x$x)
#median(x$x)
#sd(random$random_no)
#median(random$random_no)

i had to comment out the code w/ random and x because i didn’t have them in the working directory w/ kobe_basket – I moved

that wd to Week 4 thinking; didn’t move all the x and random stuff there.

data("kobe_basket")
write.table(kobe_basket, file ="kobe_basket.csv", row.names = FALSE)

This gave me a .csv file, but all variables were in the 1st column.I deleted it.

write.csv( kobe_basket, file = "kobe_basket.csv", row.names = FALSE)

This gave me a kobe_basket.csv file in my WD exactly as it should, and in the Global Environment, it shows as having 133 obs. of

6 variables, just like it should. But to run sd and median, i had to delete the OT rows.

#mean(kobe_basket$quarter)
#sd(kobe_basket$quarter)
#median(kobe_basket$quarter)

This gave me an error; couldn’t process the data. Had to delete the OT rows. I had to delete this because it had the alpha data

and the descriptives wouldn’t process.

#after deleting the OT rows
kobe_basket <- read.csv("kobe_basket.csv", header = TRUE)
mean(kobe_basket$quarter)
## Warning in mean.default(kobe_basket$quarter): argument is not numeric or
## logical: returning NA
## [1] NA
sd(kobe_basket$quarter)
## Warning in var(if (is.vector(x) || is.factor(x)) x else as.double(x), na.rm =
## na.rm): NAs introduced by coercion
## [1] NA
median(kobe_basket$quarter)
## [1] "2"

This worked. So what i learned is if I create a vector or matrix or data frame, I must first read it into r, then I can work

w/ it, write it, etc. But it seems I must read it 1st.