Question

Although there is a big difference in costs between two electric vehicles, model 1 and model 2, is there a difference in the range of miles for these vehicles between charges? Suppose that the results of driving tests are as follows.

Car	Mean	Standard Deviation	Sample Size
model 1	232.6	12.5	40
model 2	235.3	16.3	40

(a)

Calculate a point estimate for the difference in the average ranges (in miles) between charges for a model 1 car and a model 2 car. (Use μ_{model 1} − μ_{model 2}.)

  mi

What is the 95% margin of error (in miles) for the point estimate you found? (Round your answer to three decimal places.)

  mi

(b)

Find a 99% confidence interval estimate for the difference in the average ranges (in miles) between charges for these electric models. (Use μ_{model 1} − μ_{model 2}. Round your answers to two decimal places.)

  mi to   mi

Answer 1

Given ni : 40 7 = 232.6 Si = 12.5 n2=40 X2= 235.3 S2 = 16.3 ca) point estimate = Ñ -2 : 232.6 - 235.3 - -27 (4) Margin of Error ME : +* 5,2 522 t na ME - 1.9908 1(12.5) ✓ 40 ME : 6.466 (16.312, (+*31.9908, at -0.0251 40 Idf=nith 2-2=78, from t-table (6 ggr confidence interval is (x - X 2) + +* si S2² ni na 60206 = 1353) 2.54 Kent Cugat - 2.7 8,57 The 99% confidence interval is (-11.27, 5.87 )