1. In a random sample of 40 refrigerators, the mean repair cost was $150. Assume the population standard deviation σ = $15.5. a. Construct a 99% confidence interval for the population mean repair cost. Interpret the

interval in the context of the problem. [Use Algebra]

b. Repeat exercise 1(a), changing the sample size to n = 60. Which confidence interval has

better estimate? Why? Explain? [Use Algebra]

c. Repeat exercise 1(a), using a population standard deviation of σ = $19.5. Which

confidence interval is wider? Explain? [Use Algebra]

Jamie went to home depot.she bought 25 bags of soil that cost $9 per bag.she bought 15 pots at $8 each, and she bought 23 bags of pebbles at $15 each.she used a coupon that gave her $5 off for every 100 dollars she spent. how much did jamie pay at the end?

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 20 = x a. 5, 4 b. -5, -4 c. -5, 4 d. 5, -4

In may you used 400 kilowatt-hours of energy for electricity. a. calculate the total electrical energy use in joules. b. calculate your average power use in watts. c. assume that your power supplier generates electricity by burning oil. note that 1 liter of oil releases 12 million joules of energy. how much oil is needed to generate the electricity you use? give your answer in both liters and gallons. a. the total electrical energy use was nothing _ joules. (type an integer or a decimal.) b. the average power use is nothing _ watts. (round to the nearest whole number as needed.) c. to generate the electricity you used, nothing _ l is needed. (round to the nearest whole number as needed.) to generate the electricity you used, nothing _ gal is needed. (round to two decimal places as needed.)