Answer:
Hector's kite is 61.84 feet from the ground.
Step-by-step explanation:
The angle of elevation of the kite is 42°15’30” when converted to decimals, it is ≅
Let the height of the kite to the horizontal of angle of elevation be represented as x. Applying the trigonometric function to the sketch of Hector's kite,
Sin θ =
Sin =
⇒ x = 86 x Sin
= 86 x 0.6725
= 57.835
x ≅ 57.84 feet
The height of Hector's kite from the ground = x + 4
= 57.84 + 4
= 61.84 feet
121 is big enough to assume normality and not worry about the t distribution. By the 68-95-99.7 rule a 95% confidence interval includes plus or minus two standard deviations. So 95% of the cars will be in the mph range
The question is a bit vague, but it seems we're being asked for the 95% confidence interval on the average of 121 cars. The 121 is a hint of course.
The standard deviation of the average is in general the standard deviation of the individual samples divided by the square root of n:
So repeating our experiment of taking the average 121 cars over and over, we expect 95% of the averages to be in the mph range
That's probably the answer they're looking for.