UNIT 2

UNIT 2 CHEAT SHEET - Test Review

Unit 2 Review Guide - Quick Reference

Temperature & Signed Numbers

Temperature Difference: Subtract lowest from highest (watch signs!)

  • Example: 13°F - (-3°F) = 16°F difference

Temperature Conversions:

  • Celsius to Fahrenheit: F = (9/5)C + 32

  • Fahrenheit to Celsius: C = (F - 32)/1.8

Calculator Tip: Use the (-) key for negative numbers, not the subtraction key!

Absolute Value: Distance from zero (always positive)

  • |-4| = 4 and |4| = 4

Patterns & Sequences

Look for the rule:

  • Adding/subtracting the same number each time?

  • Multiplying by the same number?

  • Pattern in differences between terms?

Example: 4, 7, 10, 13... (add 3 each time)

Probability Basics

Formula: P(Event) = (Ways it can happen) / (Total possible outcomes)

Key Concepts:

  • Probability is always between 0 and 1

  • P(not A) = 1 - P(A)

  • Multiplication Principle: If A ways to do one thing and B ways to do another, then A × B total ways

Common Problems:

  • Coin flips: 2 outcomes per coin

  • Dice: 6 outcomes per die

  • Cards: 52 total, 4 suits of 13 cards each

Metric Conversions

Remember: King Henry Died By Drinking Chocolate Milk

kilo (k)

hecto (h)

deka (da)

BASE

deci (d)

centi (c)

milli (m)

×1000

×100

×10

meter/liter/gram

×0.1

×0.01

×0.001

Conversion Strategy:

  • Count spaces in the chart = number of decimal places to move

  • Moving right (smaller units) → move decimal right (bigger number)

  • Moving left (larger units) → move decimal left (smaller number)

US/Metric Conversions

Key Conversions to Remember:

  • 1 inch ≈ 2.54 cm

  • 1 mile ≈ 1.609 km

  • 1 pound ≈ 0.45 kg (or 2.2 lb ≈ 1 kg)

  • 1 quart ≈ 0.9464 L

Dimensional Analysis: Multiply by conversion factors so units cancel

  • Example: 60 miles/1 hour × 1.609 km/1 mile = 96.54 km/hour

Logic & Venn Diagrams

Regions in Venn Diagrams:

  • Overlap = "AND" (both conditions true)

  • Either circle = "OR" (at least one condition true)

  • Outside both = neither condition

  • In math, "OR" is inclusive (can include both)

Two-Way Tables & Counting

Structure:

  • Rows and columns for two categorical variables

  • Always include totals!

  • Read carefully: "of" indicates the whole/denominator

Calculating Proportions:

  • Proportion = Part / Whole

  • Always identify what the "whole" is (look for "of")

  • Convert to percent: multiply decimal by 100

Data Collection Vocabulary

Population: Entire group of interest Sample: Part of population actually measured Sample Statistic: Number describing the sample (what we calculate) Population Parameter: Number describing the population (what we want to know)

Types of Bias:

  • Sampling Bias: Sample doesn't represent population

  • Voluntary Response Bias: Only people who care strongly respond

Types of Variables:

  • Categorical: Qualities/categories (words or yes/no)

  • Numerical: Counts or measurements (numbers with meaning)

Margin of Error:

  • Confidence Interval = Sample Statistic ± Margin of Error

  • Gives range for the true population parameter

Graph Types for Categorical Data

Bar Chart: Shows frequency/count for each category

  • Bars don't touch

  • Good for comparing categories

Pie Chart: Shows parts of a whole

  • Each slice = percentage of total

  • All slices add to 100%

When reading graphs: Always estimate carefully and round appropriately!