From d57290d0d2815c21d90d02c5c7196e8f23fa75f5 Mon Sep 17 00:00:00 2001
From: nadiaenh <nadia.enhaili@gmail.com>
Date: Fri, 3 Mar 2023 01:22:36 -0800
Subject: [PATCH 1/2] working skeleton for Mean in SummaryStats

---
 src/SummaryStats.jl | 71 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 src/SummaryStats.jl

diff --git a/src/SummaryStats.jl b/src/SummaryStats.jl
new file mode 100644
index 00000000..97ea20c9
--- /dev/null
+++ b/src/SummaryStats.jl
@@ -0,0 +1,71 @@
+"""
+    SummaryStats
+
+Supertype for every type of summary statistic. 
+
+"""
+
+abstract type SummaryStats end
+
+"""
+    Calculate confidence intervals for given estimates.
+
+"""
+
+function confint(estimate::Float64, std_dev::Float64; type::String = "normal", alpha::Float64 = 0.05)
+    # Parse type of CI & calculate critical value
+    if type == "normal"
+        critical_value = quantile(Normal(),1-alpha/2)
+    end
+    # Calculate upper and lower estimates
+    lower = estimate .- critical_value .* std_dev
+    upper = estimate .+ critical_value .* std_dev
+    return (lower=lower, upper=upper)
+end
+
+"""
+
+    Mean <: SummaryStats
+
+Population mean estimate for a column of a SurveyDesign object.
+
+# Arguments:
+- `x::Symbol`: the column to compute population mean statistics for.
+- `design::SurveyDesign`: a SurveyDesign object.
+
+```jldoctest
+julia> using Survey;
+julia> apiclus1 = load_data("apiclus1");
+julia> dclus1 = SurveyDesign(apiclus1; clusters=:dnum, strata=:stype, weights=:pw);
+
+julia> api00_mean = Mean(:api00, dclus1)
+(x = :api00, estimate = 644.1693989071047, std_dev = 105.74886663549471)
+
+julia> api00_mean.estimate
+644.1693989071047
+
+julia> api00_mean.std_dev
+105.74886663549471
+
+julia> api00_mean.CI
+(lower = 436.90542889560527, upper = 851.4333689186041)
+
+```
+
+# TODO add :
+#std_err = stderror(design, x)              # standard error of the estimate of the mean
+
+"""
+
+struct Mean <: SummaryStats
+    x::Symbol
+    design::SurveyDesign
+end
+
+function Mean(x::Symbol, design::SurveyDesign)
+    column = design.data[!, x]
+    estimate = mean(column, weights(design.data[!, design.weights]))
+    std_dev = std(column)
+    CI = confint(estimate, std_dev)
+    return (x=column, estimate=estimate, std_dev=std_dev, CI=CI)
+end
\ No newline at end of file

From 88b52d75fe4ac38afd2a43399d24aee5d5baaa64 Mon Sep 17 00:00:00 2001
From: nadiaenh <nadia.enhaili@gmail.com>
Date: Fri, 3 Mar 2023 01:26:47 -0800
Subject: [PATCH 2/2] ran format

---
 src/SummaryStats.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/SummaryStats.jl b/src/SummaryStats.jl
index 97ea20c9..911237e2 100644
--- a/src/SummaryStats.jl
+++ b/src/SummaryStats.jl
@@ -12,10 +12,10 @@ abstract type SummaryStats end
 
 """
 
-function confint(estimate::Float64, std_dev::Float64; type::String = "normal", alpha::Float64 = 0.05)
+function confint(estimate::Float64, std_dev::Float64; type::String="normal", alpha::Float64=0.05)
     # Parse type of CI & calculate critical value
     if type == "normal"
-        critical_value = quantile(Normal(),1-alpha/2)
+        critical_value = quantile(Normal(), 1 - alpha / 2)
     end
     # Calculate upper and lower estimates
     lower = estimate .- critical_value .* std_dev