Records of 40 used passenger cars and 40 used pickup trucks (none used commercially) were randomly selected to investigate whether there was any difference in the mean time in years that they were kept by the original owner before being sold. For cars the mean was 5.3 years with standard deviation 2.2 years. For pickup trucks the mean was 7.1 years with standard deviation 3.0 years. Construct the 95% confidence interval for the difference in the means based on these data

The 95% confidence interval for the difference in means = (-2.953, -0.647)

Step-by-step explanation:

The confidence interval for difference in means formula =

μ1 - μ2 ± z × √(σ²1/n1 + σ²2/n2)

Where

σ = standard deviation

n = number of samples

μ = mean

Passenger cars = 1

Pick up trucks = 2

μ1 =5.3 , σ1 =2.2 , n2 = 40

μ1 =7.1, σ1 =3.0 , n2 = 40

z = 95 % confidence interval = 1.96

μ1 - μ2 ± z × √(σ²1/n1 + σ²2/n2)

= 5.3 - 7.1 + 1.96 × √2.2²/40 + 3.0²/40

= -1.8 ± 1.96× √0.121 + 0.225

= -1.8 ± 1.96 ×√0.346

= -1.8 ± 1.96 × 0.5882176468

Confidence interval = -1.8 ± 1.1529065877

= -1.8 - 1.1529065877

= -2.9529065877

≈ -2.953

= -1.8 + 1.1529065877

= -0.6470934123

≈ -0.647

Therefore, the 95% confidence interval for the difference in means = (-2.953, -0.647)

dont trust me im no expert these losers made me fail a test bro this sucks

step-by-step explanation:

d 25 pi/6

step-by-step explanation:

the diameter is 10 inches

the radius is 1/2 of the diameter or 5 inches

the area of the circle is

a = pi r^2

  = pi 5^2

  = 25 pi

the slice is 60 degrees of the entire circle.

60 degrees out of 360   60/360 = 1/6

the area of the slice is 1/6 of the circle

a slice = 1/6 a circle

a slice = 1/6 * 25 pi