Police on a heavily traveled highway claim that the average car exceeds the speed limit of 65 mph by more than 10 mph. A random sample of 50 cars is evaluated and found to have an average speed of 82.5 mph with a standard deviation for this sample of 7.3 mph. Determine the 95% confidence interval for this example, state the null and alternative hypothesis about the police’s claim and determine if the claim is indeed correct at a significance level of α=0.05

29.5977692753

step-by-step explanation:

a=24; b=12

step-by-step explanation:

a/b=2: 1

a=2b

36/(1+2)=12

b=12

a=24

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4