feat(lessons): add lessons from client db

src/pages/student/lessons/CollectingDataLesson.tsx

@@ -0,0 +1,405 @@
+import React, { useRef, useState, useEffect } from "react";
+import {
+  ArrowDown,
+  Check,
+  BookOpen,
+  Target,
+  Scale,
+  Layers,
+} from "lucide-react";
+import SamplingVisualizerWidget from "../../../components/lessons/SamplingVisualizerWidget";
+import StudyDesignWidget from "../../../components/lessons/StudyDesignWidget";
+import ConfidenceIntervalWidget from "../../../components/lessons/ConfidenceIntervalWidget";
+import Quiz from "../../../components/lessons/Quiz";
+import {
+  COLLECTING_DATA_QUIZ,
+  INFERENCES_QUIZ_DATA,
+} from "../../../utils/constants";
+
+interface LessonProps {
+  onFinish?: () => void;
+}
+
+const CollectingDataLesson: React.FC<LessonProps> = ({ onFinish }) => {
+  const [activeSection, setActiveSection] = useState(0);
+  const sectionsRef = useRef<(HTMLElement | null)[]>([]);
+
+  const scrollToSection = (index: number) => {
+    setActiveSection(index);
+    sectionsRef.current[index]?.scrollIntoView({
+      behavior: "smooth",
+      block: "start",
+    });
+  };
+
+  useEffect(() => {
+    const observer = new IntersectionObserver(
+      (entries) => {
+        entries.forEach((entry) => {
+          if (entry.isIntersecting) {
+            const index = sectionsRef.current.indexOf(
+              entry.target as HTMLElement,
+            );
+            if (index !== -1) setActiveSection(index);
+          }
+        });
+      },
+      { rootMargin: "-20% 0px -60% 0px" },
+    );
+    sectionsRef.current.forEach((section) => {
+      if (section) observer.observe(section);
+    });
+    return () => observer.disconnect();
+  }, []);
+
+  const SectionMarker = ({
+    index,
+    title,
+    icon: Icon,
+  }: {
+    index: number;
+    title: string;
+    icon: any;
+  }) => {
+    const isActive = activeSection === index;
+    const isPast = activeSection > index;
+    return (
+      <button
+        onClick={() => scrollToSection(index)}
+        className={`flex items-center gap-3 p-3 w-full rounded-lg transition-all ${isActive ? "bg-white shadow-md border border-amber-100" : "hover:bg-slate-100"}`}
+      >
+        <div
+          className={`w-8 h-8 rounded-full flex items-center justify-center shrink-0 ${isActive ? "bg-amber-600 text-white" : isPast ? "bg-amber-400 text-white" : "bg-slate-200 text-slate-500"}`}
+        >
+          {isPast ? (
+            <Check className="w-4 h-4" />
+          ) : (
+            <Icon className="w-4 h-4" />
+          )}
+        </div>
+        <div className="text-left">
+          <p
+            className={`text-sm font-bold ${isActive ? "text-amber-900" : "text-slate-600"}`}
+          >
+            {title}
+          </p>
+        </div>
+      </button>
+    );
+  };
+
+  const allQuizzes = [...COLLECTING_DATA_QUIZ, ...INFERENCES_QUIZ_DATA];
+
+  return (
+    <div className="flex flex-col lg:flex-row min-h-screen">
+      <aside className="w-full lg:w-64 lg:fixed lg:top-20 lg:bottom-0 lg:overflow-y-auto p-4 border-r border-slate-200 bg-slate-50 z-0 hidden lg:block">
+        <nav className="space-y-2">
+          <SectionMarker index={0} title="Sampling & Bias" icon={Scale} />
+          <SectionMarker index={1} title="Study Design" icon={Layers} />
+          <SectionMarker index={2} title="Confidence Intervals" icon={Target} />
+          <SectionMarker index={3} title="Practice" icon={BookOpen} />
+        </nav>
+      </aside>
+
+      <div className="flex-1 lg:ml-64 p-6 md:p-12 max-w-4xl mx-auto">
+        {/* Section 1: Sampling & Bias */}
+        <section
+          ref={(el) => {
+            sectionsRef.current[0] = el;
+          }}
+          className="min-h-screen flex flex-col justify-center mb-24 pt-20 lg:pt-0"
+        >
+          <h2 className="text-4xl font-extrabold text-slate-900 mb-6">
+            Sampling & Bias
+          </h2>
+          <div className="prose prose-slate text-lg text-slate-600 mb-8">
+            <p>
+              To generalize results to a population, your sample must be{" "}
+              <strong>representative</strong>. The best way to achieve this is
+              through <strong>random sampling</strong>. Convenience samples
+              (e.g., asking friends) introduce <strong>bias</strong> — they
+              systematically over- or under-represent parts of the population.
+            </p>
+            <div className="mt-5 overflow-x-auto">
+              <table className="w-full text-sm border-collapse">
+                <thead>
+                  <tr className="bg-amber-100 text-amber-900">
+                    <th className="border border-amber-300 px-3 py-2 text-left font-bold">
+                      Method
+                    </th>
+                    <th className="border border-amber-300 px-3 py-2 text-left font-bold">
+                      Description
+                    </th>
+                    <th className="border border-amber-300 px-3 py-2 text-left font-bold">
+                      Bias Risk
+                    </th>
+                  </tr>
+                </thead>
+                <tbody className="text-slate-700">
+                  <tr className="bg-white">
+                    <td className="border border-slate-200 px-3 py-2 font-semibold">
+                      Simple Random
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2">
+                      Every individual has an equal chance of selection
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-emerald-700 font-semibold">
+                      Very Low
+                    </td>
+                  </tr>
+                  <tr className="bg-slate-50">
+                    <td className="border border-slate-200 px-3 py-2 font-semibold">
+                      Stratified
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2">
+                      Population divided into subgroups; random sample from each
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-emerald-700 font-semibold">
+                      Very Low
+                    </td>
+                  </tr>
+                  <tr className="bg-white">
+                    <td className="border border-slate-200 px-3 py-2 font-semibold">
+                      Cluster
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2">
+                      Randomly select entire subgroups (e.g., classrooms)
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-amber-700 font-semibold">
+                      Low–Medium
+                    </td>
+                  </tr>
+                  <tr className="bg-slate-50">
+                    <td className="border border-slate-200 px-3 py-2 font-semibold">
+                      Systematic
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2">
+                      Select every kth individual from a list
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-amber-700 font-semibold">
+                      Low–Medium
+                    </td>
+                  </tr>
+                  <tr className="bg-white">
+                    <td className="border border-slate-200 px-3 py-2 font-semibold">
+                      Convenience
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2">
+                      Whoever is easiest to reach (friends, passersby)
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-rose-700 font-semibold">
+                      High
+                    </td>
+                  </tr>
+                </tbody>
+              </table>
+            </div>
+            <div className="mt-4 grid md:grid-cols-2 gap-4">
+              <div className="bg-emerald-50 border border-emerald-200 rounded-xl p-4">
+                <p className="font-bold text-emerald-900 mb-1">
+                  Representative Sample
+                </p>
+                <p className="text-sm text-slate-700">
+                  Mirrors the population in all key characteristics. Allows you
+                  to generalize findings to the whole group. Achieved through
+                  random selection.
+                </p>
+              </div>
+              <div className="bg-rose-50 border border-rose-200 rounded-xl p-4">
+                <p className="font-bold text-rose-900 mb-1">Biased Sample</p>
+                <p className="text-sm text-slate-700">
+                  Systematically excludes or over-includes certain groups.
+                  Results cannot be generalized. Watch for voluntary response
+                  and convenience sampling.
+                </p>
+              </div>
+            </div>
+            <div className="mt-4 p-3 bg-amber-50 border-l-4 border-amber-500 rounded-r-lg text-sm">
+              <strong className="text-amber-900">Margin of Error:</strong> Even
+              a well-designed random sample has some uncertainty. The margin of
+              error (e.g., ±3%) tells you the range where the true population
+              value likely falls. Larger samples produce smaller margins of
+              error.
+            </div>
+          </div>
+
+          <SamplingVisualizerWidget />
+
+          <button
+            onClick={() => scrollToSection(1)}
+            className="mt-12 group flex items-center text-amber-600 font-bold hover:text-amber-800 transition-colors"
+          >
+            Next: Study Design{" "}
+            <ArrowDown className="ml-2 w-5 h-5 group-hover:translate-y-1 transition-transform" />
+          </button>
+        </section>
+
+        {/* Section 2: Study Design */}
+        <section
+          ref={(el) => {
+            sectionsRef.current[1] = el;
+          }}
+          className="min-h-screen flex flex-col justify-center mb-24"
+        >
+          <h2 className="text-4xl font-extrabold text-slate-900 mb-6">
+            Study Design: Generalization vs Causation
+          </h2>
+          <div className="prose prose-slate text-lg text-slate-600 mb-8">
+            <p>
+              Two concepts are critical here. <strong>Random sampling</strong>{" "}
+              determines whether you can extend your conclusions to the broader
+              population. <strong>Random assignment</strong> (used in
+              experiments) determines whether you can claim cause-and-effect.
+            </p>
+            <div className="mt-5 overflow-x-auto">
+              <table className="w-full text-sm border-collapse">
+                <thead>
+                  <tr className="bg-amber-100 text-amber-900">
+                    <th className="border border-amber-300 px-3 py-2"></th>
+                    <th className="border border-amber-300 px-3 py-2 text-center font-bold">
+                      Random Assignment? YES
+                    </th>
+                    <th className="border border-amber-300 px-3 py-2 text-center font-bold">
+                      Random Assignment? NO
+                    </th>
+                  </tr>
+                </thead>
+                <tbody className="text-slate-700">
+                  <tr className="bg-white">
+                    <td className="border border-slate-200 px-3 py-2 font-bold bg-amber-50 text-amber-900">
+                      Random Sampling? YES
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-center bg-emerald-50 text-emerald-800 font-semibold">
+                      Generalize + Cause & Effect
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-center bg-blue-50 text-blue-800 font-semibold">
+                      Generalize only
+                    </td>
+                  </tr>
+                  <tr className="bg-slate-50">
+                    <td className="border border-slate-200 px-3 py-2 font-bold bg-amber-50 text-amber-900">
+                      Random Sampling? NO
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-center bg-purple-50 text-purple-800 font-semibold">
+                      Cause & Effect only (for this group)
+                    </td>
+                    <td className="border border-slate-200 px-3 py-2 text-center bg-rose-50 text-rose-800 font-semibold">
+                      Neither — observe only
+                    </td>
+                  </tr>
+                </tbody>
+              </table>
+            </div>
+            <div className="mt-4 p-3 bg-amber-50 border-l-4 border-amber-500 rounded-r-lg text-sm">
+              <strong className="text-amber-900">SAT Key Rule:</strong>{" "}
+              Observational studies (no random assignment) can show{" "}
+              <em>association</em> but never <em>causation</em>. Only randomized
+              controlled experiments can establish cause-and-effect.
+            </div>
+          </div>
+          <StudyDesignWidget />
+
+          <button
+            onClick={() => scrollToSection(2)}
+            className="mt-12 group flex items-center text-amber-600 font-bold hover:text-amber-800 transition-colors"
+          >
+            Next: Confidence Intervals{" "}
+            <ArrowDown className="ml-2 w-5 h-5 group-hover:translate-y-1 transition-transform" />
+          </button>
+        </section>
+
+        {/* Section 3: Confidence Intervals & Comparing Groups */}
+        <section
+          ref={(el) => {
+            sectionsRef.current[2] = el;
+          }}
+          className="min-h-screen flex flex-col justify-center mb-24"
+        >
+          <h2 className="text-4xl font-extrabold text-slate-900 mb-6">
+            Confidence Intervals & Comparing Groups
+          </h2>
+          <div className="prose prose-slate text-lg text-slate-600 mb-8">
+            <p>
+              A <strong>Confidence Interval</strong> (Estimate ± Margin of
+              Error) gives a range where the true population value likely lies.
+              When comparing two groups, check for <strong>overlap</strong> — if
+              the intervals do not overlap, you can conclude a significant
+              difference.
+            </p>
+            <div className="mt-4 bg-amber-50 border border-amber-200 rounded-xl p-5 space-y-3">
+              <p className="font-bold text-amber-900">
+                Key Rules for Confidence Intervals
+              </p>
+              <div className="grid md:grid-cols-2 gap-3 text-sm">
+                <div className="bg-white rounded-lg p-3 border border-amber-100">
+                  <p className="font-bold text-amber-800 mb-1">
+                    Intervals Overlap
+                  </p>
+                  <p className="text-slate-700">
+                    Cannot claim a significant difference between the two
+                    groups.
+                  </p>
+                </div>
+                <div className="bg-white rounded-lg p-3 border border-amber-100">
+                  <p className="font-bold text-amber-800 mb-1">
+                    Intervals Don't Overlap
+                  </p>
+                  <p className="text-slate-700">
+                    There is a significant difference — the groups are
+                    statistically distinct.
+                  </p>
+                </div>
+              </div>
+              <div className="bg-amber-100 rounded-lg p-3 text-sm">
+                <p className="font-bold text-amber-900 mb-1">
+                  Larger Samples → Smaller Margin of Error
+                </p>
+                <p className="text-slate-700">
+                  Increasing the sample size narrows the confidence interval,
+                  giving you a more precise estimate.
+                </p>
+              </div>
+            </div>
+          </div>
+          <ConfidenceIntervalWidget />
+
+          <button
+            onClick={() => scrollToSection(3)}
+            className="mt-12 group flex items-center text-amber-600 font-bold hover:text-amber-800 transition-colors"
+          >
+            Next: Practice Quiz{" "}
+            <ArrowDown className="ml-2 w-5 h-5 group-hover:translate-y-1 transition-transform" />
+          </button>
+        </section>
+
+        {/* Section 4: Quiz */}
+        <section
+          ref={(el) => {
+            sectionsRef.current[3] = el;
+          }}
+          className="min-h-screen flex flex-col justify-center"
+        >
+          <h2 className="text-4xl font-extrabold text-slate-900 mb-8">
+            Practice Time
+          </h2>
+          {allQuizzes.map((quiz, idx) => (
+            <div key={`quiz-${idx}`} className="mb-12">
+              <Quiz data={quiz} />
+            </div>
+          ))}
+          <div className="p-8 bg-amber-900 rounded-2xl text-white text-center mt-12">
+            <h3 className="text-2xl font-bold mb-4">Topic Mastered!</h3>
+            <button
+              onClick={onFinish}
+              className="px-6 py-3 bg-white text-amber-900 font-bold rounded-full hover:bg-amber-50 transition-colors"
+            >
+              Finish Lesson ✓
+            </button>
+          </div>
+        </section>
+      </div>
+    </div>
+  );
+};
+
+export default CollectingDataLesson;