## Step $8$: Confidence Intervals for the Average Relative Skill of All Teams in Your Team's Years print$("$Confidence Interval for Average Relative Skill in the years $2013$ to $2015")$

$4$ Mean reLative skiLL of aLL teams from the years $2013-2015$

mean $=$ your$\_$years$\_$leagues$\_$df$[\text{'}$elo$\_$n$\text{'}].$mean$()$

$43$ Standard deviation of the reLative skill of all teaws from the years $2013-2015$

stdev $=$ your$\_$years$\_$leagues$\_$df$["$elo$\_$n$\text{'}].$std$()$

n$\}=\backslash$mathrm$\{$ len$($your$\_$years$\_$leagues$\_$df$)$

#Confidence interval

$-..-$ TODO: make your edits here $-..-$

stderr $=$ stdev$/($n $**0\mathrm{.}5)$

confidence$\_$level $=0\mathrm{.}95$

conf$\_$int$\_95=$ st$.$norn.interval$($confidence$\_$level, mean, stderr$)$

print$("95\%$ confidence Interval $($unrounded$)$ for Average Relative Skil$1($ELO$)$ in the years $2013$ to $2015=",$ conf$\_$int$\_95)$

print$("95\%$ confidence interval $($rounded$)$ for Average Relative Skil$1($ELO$)$ in the years $2013$ to $2015=(",$ round$($conf$\_$int$\_95[8],$

print$(*$

$")$

print$("$Python Method to calculate probability that a team has Average Relative Skill LESS than the Average Relative Skill $($ELO$)$

print$(*-$

choice$1=$ st$.$norm.sf

choice$2=$ st$.$norm.cdf

$*$H Pick the correct answer.

print$("$Which of the two choices $($choice $1$ or choice $2)$ is correct? Choice $1$ or Choice $2?")$

Confidence Interval for Average Relative Skill in the years $2013$ to $2015$

NameError

Traceback $($nost recent call last$)$

The management wants to you to calculate a $95\%$ confidence interval for the average relative skill of all teams in $2013-2015.$ You will use the variable 'elo$\_$n$\text{'}$ to respresent the relative skill of the teams. To construct a confidence interval, you will need the mean and standard error of the relative skill level in these years. The code block below calculates the mean and the standard deviation. Your edits will calculate the standard error and the confidence interval. Make the following edits to the code block below:

$1.$ Replace $??$SD$\_$VARIABLE?? with the variable name representing the standard deviation of relative skill of all teams from your years. $($Hint: the $*$standard deviation$*$ variable is in the code block below$)$

$2.$ Replace $??$CL$??$ with the confidence level of the confidence interval.

$3.$ Replace $??$MEAN$\_$VARIABLE?? with the variable name representing the mean relative skill of all teams from your years. $($Hint: the $*$mean$*$ variable is in the code block below$)$

$4.$ Replace $??$SE$\_$VARIABLE?? with the variable name representing the standard error. $($Hint: the $*$standard error$*$ variable is in the code block below$)$

The management also wants you to calculate the probability that a team in the league has a relative skill level less than that of the team that you picked. Assuming that the relative skill of teams is Normally distributed, Python methods for a Normal distribution can be used to answer this question. The code block below uses two methods from scipy.stats module in Python. Your task is to identify the correct Python method.

After you are done with your edits, click the block of code below and hit the $**$Run$**$ button above.