The method of tree ring dating gave the following years A. D. for an archaeological excavation site. Assume that the population of x values has an approximately normal distribution 1229 1257 1243 1194 1268 1316 1275 1317 1275

(a) Use a calculator with mean and standard deviation keys to find the sample mean year x and sample standard deviation s. (Round your answers to the nearest whole number.)

(b) Find a 90% confidence interval for the mean of all tree ring dates from this archaeological site. (Round your answers to the nearest whole number.)

A) Mean = 1264

Standard deviation = 37

B) CI ≈ (1241, 1287)

Step-by-step explanation:

A) Mean = Σx/n

Σx = 1229 + 1257 + 1243 + 1194 + 1268 + 1316 + 1275 + 1317 + 1275

Σx = 11374

Mean(x¯) = 11374/9

Mean(x¯) ≈ 1264

Standard deviation = √(∑(x - x¯)²/(n)

From online calculator;

Standard deviation; s ≈ 37

B) Our distribution factor is; DF = n - 1 = 9 - 1 = 8

From t-table attached, our critical value at 90% Confidence interval is t = 1.86

Formula for confidence interval is;

CI = x¯ ± t(s/√n)

CI = 1264 ± 1.86(37/√9)

CI = 1264 ± 22.94

CI ≈ (1241, 1287)

need points to ask question

step-by-step explanation:

answer: option a.

step-by-step explanation:

you know that the quadrilateral opqr ( a four sided figure) is inscribed in circle. this means that all its vertices are on the circle.

then, by definition, the opposite angles of the quadrilateral are supplementary, this means that the sum of their measures is 180 degrees.

you can observe in the figure that the angles ∠opq   and the angle ∠orq   are opposite, therefore:

then, can be used to d to calculate the measure of ∠opq