Lecture_1_revision

choose all possible answers that are measures of central tendency

• Mean

• Median

• Mode

• Second Quartile

Choose all the possible answers

• The mean is the red line and the median is the blue

• The mean is the blue line and the median is the red line

• The mean is more affected by outliers

• The median is affected by outliers

data1=c(12,80,77,1)

data2=c(550, 630, 650,700)

which data has the larger standard deviation

• data1

• data2

• Both have same Standard Deviation

What is the best measure of dispersion to Compare the dispersion of the following prices

data1_dollars=c(40, 70, 12)

data2_EGP=c(400, 1200, 770)

• Standard Deviation

• Inter Quartile Range

• Variance

• Coefficient of Variation

What this code do:

prices=c(1,6,7,8,9,10,2,3,4,5)

q=quantile(prices,0.1)

• Brings the value that 10% of data greater than it

• Brings the value that 10% of data less than it

• Negative Skewed

• Positive Skewed

• Symmetric

If you want to test correlation between two numerical variables, and both variables are Normally distributed and with no outliers. What is the best test of correlation?

• None of them

• Kendall's

• Spearman's

• Pearson's

If you want to select rows in dataframe that have bwt greater than 2550, which dplyr functions should be use?

• df%>%

  select(bwt==2550)

• df%>%

  select(bwt>2550)

• df%>%

  filter(bwt>2550)

• None of the answers are true

df%>%

dplyr::filter(smoke==0)

:: is used to tell the R to take the function filter from package dplyr

• True

• False

The dplyr function that is responsible to add new variables (columns) or change existing variables is:

• filter()

• select_max()

• select()

• mutate()