Math 20 Math 25 Student Resources davidvs.net

Math 25 Bell Curve Homework

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S51. In which month does this household use the most electricity?

either January or February
either April or May
either July or August
either October or November

S52. Which month has the least deviation from year to year?

April May June July

S53. Someone asks, "What is this household's typical monthly electrical usage?" What would make a numeric answer to this question meaningful?

Let's limit the question to a season instead of the entire year
Let's look for most common, not most representative
Let's discard the data before December 2018 as obsolete
All of the above

S54. When did this family replace their old electric furnace with a modern and more efficient heat pump?

December 2017 December 2018 December 2019

S55. The total electrical usage for 2017 was 14,780 kilowatt hours. The total electrical usage for 2019 was 11,513 kilowatt hours. How much less electricity was used in 2019?

272 kilowatt hours 3,267 kilowatt hours

S56. Electricity costs an average of 11.3 cents per kilowatt hour. How much less money was spent on electricity in 2019 than in 2017?

\$31 \$36 \$369 \$3,067

S57. What was the percentage decrease of this household's total annual electricity usage when comparing 2017 to 2019?

22% 28% 78% 128%

S58. In this city 80% percent of the electric power is from carbon-free hydroelectric energy, making an overall CO2 emission of 16.2 grams per kilowatt hour. How many kilograms of CO2 did this household's electric use create in 2019?

37 kg 47 kg 187 kg 239 kg

S59. A typical gasoline automobile's emission is 8.8 kilograms of CO2 per gallon. This household's car gets 30 miles per gallon. How many miles would they need to drive to the equal CO2 emissions of their annual electricity use?