$1.$ Using the gapminder data in the lesson, do the following:

i$)$ use $`$filter$`$ to select all countries with the following arguments:

a$)$ life expectancy larger than $60$ years.

b$)$ United Kingdom and Vietnam and years greater than $1990.$

ii$)$ use $`$arrange$`$ and $`$slice$`$ to select the countries with the top $15$ GDP per capital $`$gdpPercap$`.$ Use the pipe $`\%>\%`$ operator to string multiple functions.

iii$)$ use $`$mutate$`$ to create a new variable called $`$gdpPercap$\_$lifeExp$`$ which is the quotient of $`$gdpPercap$`$ and $`$lifeExp$`$ and display the output.

iv$)$ use $`$summarise$`$ to find the average or mean value of the variable $`$gdpPercap$\_$lifeExp$`$ created in part $($iii$).$

v$)$ use $`$group$\_$by$`$ to group the countries by $`$continent$`$; and $`$summarise$`$ to compute the average life expectancy $`$lifeExp$`$ within each continent. Use the pipe $`\%>\%`$ operator to string multiple functions.